Buzoianu, Stefan G; Walsh, Maria C; Rea, Mary C; O'Sullivan, Orla; Cotter, Paul D; Ross, R Paul; Gardiner, Gillian E; Lawlor, Peadar G
The objective of this study was to investigate if feeding genetically modified (GM) MON810 maize expressing the Bacillus thuringiensis insecticidal protein (Bt maize) had any effects on the porcine intestinal microbiota. Eighteen pigs were weaned at ~28 days and, following a 6-day acclimatization period, were assigned to diets containing either GM (Bt MON810) maize or non-GM isogenic parent line maize for 31 days (n = 9/treatment). Effects on the porcine intestinal microbiota were assessed through culture-dependent and -independent approaches. Fecal, cecal, and ileal counts of total anaerobes, Enterobacteriaceae, and Lactobacillus were not significantly different between pigs fed the isogenic or Bt maize-based diets. Furthermore, high-throughput 16S rRNA gene sequencing revealed few differences in the compositions of the cecal microbiotas. The only differences were that pigs fed the Bt maize diet had higher cecal abundance of Enterococcaceae (0.06 versus 0%; P < 0.05), Erysipelotrichaceae (1.28 versus 1.17%; P < 0.05), and Bifidobacterium (0.04 versus 0%; P < 0.05) and lower abundance of Blautia (0.23 versus 0.40%; P < 0.05) than pigs fed the isogenic maize diet. A lower enzyme-resistant starch content in the Bt maize, which is most likely a result of normal variation and not due to the genetic modification, may account for some of the differences observed within the cecal microbiotas. These results indicate that Bt maize is well tolerated by the porcine intestinal microbiota and provide additional data for safety assessment of Bt maize. Furthermore, these data can potentially be extrapolated to humans, considering the suitability of pigs as a human model.
Ahmad, Aqeel; Negri, Ignacio; Oliveira, Wladecir; Brown, Christopher; Asiimwe, Peter; Sammons, Bernard; Horak, Michael; Jiang, Changjian; Carson, David
As part of an environmental risk assessment, the potential impact of genetically modified (GM) maize MON 87411 on non-target arthropods (NTAs) was evaluated in the field. MON 87411 confers resistance to corn rootworm (CRW; Diabrotica spp.) by expressing an insecticidal double-stranded RNA (dsRNA) transcript and the Cry3Bb1 protein and tolerance to the herbicide glyphosate by producing the CP4 EPSPS protein. Field trials were conducted at 14 sites providing high geographic and environmental diversity within maize production areas from three geographic regions including the U.S., Argentina, and Brazil. MON 87411, the conventional control, and four commercial conventional reference hybrids were evaluated for NTA abundance and damage. Twenty arthropod taxa met minimum abundance criteria for valid statistical analysis. Nine of these taxa occurred in at least two of the three regions and in at least four sites across regions. These nine taxa included: aphid, predatory earwig, lacewing, ladybird beetle, leafhopper, minute pirate bug, parasitic wasp, sap beetle, and spider. In addition to wide regional distribution, these taxa encompass the ecological functions of herbivores, predators and parasitoids in maize agro-ecosystems. Thus, the nine arthropods may serve as representative taxa of maize agro-ecosystems, and thereby support that analysis of relevant data generated in one region can be transportable for the risk assessment of the same or similar GM crop products in another region. Across the 20 taxa analyzed, no statistically significant differences in abundance were detected between MON 87411 and the conventional control for 123 of the 128 individual-site comparisons (96.1%). For the nine widely distributed taxa, no statistically significant differences in abundance were detected between MON 87411 and the conventional control. Furthermore, no statistically significant differences were detected between MON 87411 and the conventional control for 53 out of 56 individual
Bakan, B; Melcion, D; Richard-Molard, D; Cahagnier, B
Fungi of the genus Fusarium are common fungal contaminants of maize and are also known to produce mycotoxins. Maize that has been genetically modified to express a Bt endotoxin has been used to study the effect of insect resistance on fungal infection of maize grains by Fusarium species and their related mycotoxins. Maize grain from Bt hybrids and near-isogenic traditional hybrids was collected in France and Spain from the 1999 crop, which was grown under natural conditions. According to the ergosterol level, the fungal biomass formed on Bt maize grain was 4-18 times lower than that on isogenic maize. Fumonisin B(1) grain concentrations ranged from 0.05 to 0.3 ppm for Bt maize and from 0.4 to 9 ppm for isogenic maize. Moderate to low concentrations of trichothecenes and zearalenone were measured on transgenic as well as on non-transgenic maize. Nevertheless, significant differences were obtained in certain regions. The protection of maize plants against insect damage (European corn borer and pink stem borer) through the use of Bt technology seems to be a way to reduce the contamination of maize by Fusarium species and the resultant fumonisins in maize grain grown in France and Spain.
Pálinkás, Zoltán; Kiss, József; Zalai, Mihály; Szénási, Ágnes; Dorner, Zita; North, Samuel; Woodward, Guy; Balog, Adalbert
Four genetically modified (GM) maize (Zea mays L.) hybrids (coleopteran resistant, coleopteran and lepidopteran resistant, lepidopteran resistant and herbicide tolerant, coleopteran and herbicide tolerant) and its non-GM control maize stands were tested to compare the functional diversity of arthropods and to determine whether genetic modifications alter the structure of arthropods food webs. A total number of 399,239 arthropod individuals were used for analyses. The trophic groups' number and the links between them indicated that neither the higher magnitude of Bt toxins (included resistance against insect, and against both insects and glyphosate) nor the extra glyphosate treatment changed the structure of food webs. However, differences in the average trophic links/trophic groups were detected between GM and non-GM food webs for herbivore groups and plants. Also, differences in characteristic path lengths between GM and non-GM food webs for herbivores were observed. Food webs parameterized based on 2-year in-field assessments, and their properties can be considered a useful and simple tool to evaluate the effects of Bt toxins on non-target organisms.
Eveland, Andrea L; Satoh-Nagasawa, Namiko; Goldshmidt, Alexander; Meyer, Sandra; Beatty, Mary; Sakai, Hajime; Ware, Doreen; Jackson, David
Genome-wide expression signatures detect specific perturbations in developmental programs and contribute to functional resolution of key regulatory networks. In maize (Zea mays) inflorescences, mutations in the RAMOSA (RA) genes affect the determinacy of axillary meristems and thus alter branching patterns, an important agronomic trait. In this work, we developed and tested a framework for analysis of tag-based, digital gene expression profiles using Illumina's high-throughput sequencing technology and the newly assembled B73 maize reference genome. We also used a mutation in the RA3 gene to identify putative expression signatures specific to stem cell fate in axillary meristem determinacy. The RA3 gene encodes a trehalose-6-phosphate phosphatase and may act at the interface between developmental and metabolic processes. Deep sequencing of digital gene expression libraries, representing three biological replicate ear samples from wild-type and ra3 plants, generated 27 million 20- to 21-nucleotide reads with frequencies spanning 4 orders of magnitude. Unique sequence tags were anchored to 3'-ends of individual transcripts by DpnII and NlaIII digests, which were multiplexed during sequencing. We mapped 86% of nonredundant signature tags to the maize genome, which associated with 37,117 gene models and unannotated regions of expression. In total, 66% of genes were detected by at least nine reads in immature maize ears. We used comparative genomics to leverage existing information from Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) in functional analyses of differentially expressed maize genes. Results from this study provide a basis for the analysis of short-read expression data in maize and resolved specific expression signatures that will help define mechanisms of action for the RA3 gene.
Liu, Pengfei; He, Xiaoyun; Chen, Delong; Luo, Yunbo; Cao, Sishuo; Song, Huan; Liu, Ting; Huang, Kunlun; Xu, Wentao
The cry1Ac-M gene, coding one of Bacillus thuringiensis (Bt) crystal proteins, was introduced into maize H99 × Hi IIB genome to produce insect-resistant GM maize BT-38. The food safety assessment of the BT-38 maize was conducted in Sprague-Dawley rats by a 90-days feeding study. We incorporated maize grains from BT-38 and H99 × Hi IIB into rodent diets at three concentrations (12.5%, 25%, 50%) and administered to Sprague-Dawley rats (n=10/sex/group) for 90 days. A commercialized rodent diet was fed to an additional group as control group. Body weight, feed consumption and toxicological response variables were measured, and gross as well as microscopic pathology were examined. Moreover, detection of residual Cry1Ac-M protein in the serum of rats fed with GM maize was conducted. No death or adverse effects were observed in the current feeding study. No adverse differences in the values of the response variables were observed between rats that consumed diets containing GM maize BT-38 and non-GM maize H99 × Hi IIB. No detectable Cry1Ac-M protein was found in the serum of rats after feeding diets containing GM maize for 3 months. The results demonstrated that BT-38 maize is as safe as conventional non-GM maize.
Genome-wide expression signatures detect specific perturbations in developmental programs and contribute to functional resolution of key regulatory networks. In maize (Zea mays) inflorescences, mutations in the RAMOSA (RA) genes affect determinacy of axillary meristems and thus alter branching patt...
Chrenková, Mária; Sommer, A; Ceresnáková, Zuzana; Nitrayová, Sona; Prostredná, Miroslava
The aim of this study was to determine the composition and nutritional value of conventional and transgenic, so-called Roundup Ready (RR) maize with an introduced gene of glyphosate resistance. Crude protein, crude fibre, ash, fat, starch, sugar, amino acids, fatty acid and macroelement levels were determined by chemical analysis. In both maize lines a low level of Ca (0.15 g.kg-1 DM) and of the essential amino acids lysine and tryptophan (2.6 and 1.7 g.kg-1 DM, respectively) were observed. In the biological experiment carried out on rats the tested maize lines were the only dietary sources of nitrogen, thus, the experimental diets contained 9% CP in dietary dry matter. In the feeding experiment no significant differences in the protein efficiency ratio (PER) were observed between groups receiving conventional or transgenic maize (1.51 and 1.41, respectively). Also almost equal results were obtained in the balance experiments. Both maize lines revealed a high nitrogen digestibility (84.9 and 84.5%, respectively) and the net protein utilization amounted to 63.5 and 63.2%, respectively. From these results can be concluded that regarding nutrient composition and utilisation, genetically modified (RR) maize is equivalent to isogenic maize.
Chowdhury, Emdadull H; Mikami, Osamu; Murata, Hideo; Sultana, Parvin; Shimada, Nobuaki; Yoshioka, Miyako; Guruge, Keerthi S; Yamamoto, Sachiko; Miyazaki, Shigeru; Yamanaka, Noriko; Nakajima, Yasuyuki
The presence of maize intrinsic and recombinant cry1Ab genes in the gastrointestinal (GI) contents, peripheral blood mononuclear cells (PBMC), and visceral organs of calves fed genetically modified Bt11 maize was examined by PCR in a subchronic 90-day performance study. Samples were collected from six Japanese Black/Holstein calves fed Bt11 maize and from six calves fed non-Bt maize. Fragments of maize zein (Ze1), invertase, chloroplast, and cry1Ab were detected inconsistently in the rumen fluid and rectal contents 5 and 18 h after feeding. The chloroplast DNA fragments of ribulose-1,5-bisphosphate carboxylase/oxygenase and tRNA were detected inconsistently in the PBMC, the visceral organs, and the longissimus muscle, while the cry1Ab gene was never detected in PBMC or in the visceral organs. These results suggest that feed-derived maize DNA was mostly degraded in the GI tract but that fragmented DNA was detectable in the GI contents as a possible source of transfer to calf tissues. These results also suggest that the recombinant cry1Ab genes were not transferred to the PBMC and tissues of calves fed Bt11 maize.
Brodmann, Peter D; Ilg, Evelyn C; Berthoud, Hélène; Herrmann, Andre
Quantitative detection methods are needed for enforcement of the recently introduced labeling threshold for genetically modified organisms (GMOs) in food ingredients. This labeling threshold, which is set to 1% in the European Union and Switzerland, must be applied to all approved GMOs. Four different varieties of maize are approved in the European Union: the insect-resistant Bt176 maize (Maximizer), Btl 1 maize, Mon810 (YieldGard) maize, and the herbicide-tolerant T25 (Liberty Link) maize. Because the labeling must be considered individually for each ingredient, a quantitation system for the endogenous maize content is needed in addition to the GMO-specific detection systems. Quantitative real-time polymerase chain reaction detection methods were developed for the 4 approved genetically modified maize varieties and for an endogenous maize (invertase) gene system.
Akiyama, Hiroshi; Sakata, Kozue; Kondo, Kazunari; Tanaka, Asako; Liu, Ming S; Oguchi, Taichi; Furui, Satoshi; Kitta, Kazumi; Hino, Akihiro; Teshima, Reiko
In many countries, the labeling of grains and feed- and foodstuffs is mandatory if the genetically modified organism (GMO) content exceeds a certain level of approved GM varieties. The GMO content in a maize sample containing the combined-trait (stacked) GM maize as determined by the currently available methodology is likely to be overestimated. However, there has been little information in the literature on the mixing level and varieties of stacked GM maize in real sample grains. For the first time, the GMO content of non-identity-preserved (non-IP) maize samples imported from the United States has been successfully determined by using a previously developed individual kernel detection system coupled to a multiplex qualitative PCR method followed by multichannel capillary gel electrophoresis system analysis. To clarify the GMO content in the maize samples imported from the United States, determine how many stacked GM traits are contained therein, and which GM trait varieties frequently appeared in 2005, the GMO content (percent) on a kernel basis and the varieties of the GM kernels in the non-IP maize samples imported from the United States were investigated using the individual kernel analysis system. The average (+/-standard deviation) of the GMO contents on a kernel basis in five non-IP sample lots was determined to be 51.0+/-21.6%, the percentage of a single GM trait grains was 39%, and the percentage of the stacked GM trait grains was 12%. The MON810 grains and NK603 grains were the most frequent varieties in the single GM traits. The most frequent stacked GM traits were the MON810xNK603 grains. In addition, the present study would provide the answer and impact for the quantification of GM maize content in the GM maize kernels on labeling regulation.
Svobodová, Z; Skoková Habuštová, O; Boháč, J; Sehnal, F
Staphylinid beetles are recommended bioindicators for the pre-market environmental risk assessment of genetically modified (GM) insect protected maize expressing the Cry3Bb1 toxin. Our multiannual study is a unique European analysis of a staphylinid community within a 14 ha maize field. GM maize, its near-isogenic hybrid (with or without insecticide treatment), and two other reference hybrids were each grown in five 0.5 ha plots. The opportunity for exposure to Cry toxin from plant residues ploughed into the soil was shown by the presence of saprophagous dipteran larvae that are common prey of predatory staphylinid species and hosts of the parasitoid species. 2587 individuals belonging to 77 staphylinid species were sampled using pitfall traps. Lesteva longoelytrata (31%), Oxypoda acuminata (12%), Aloconota sulcifrons (8%) and Anotylus rugosus (7%) were the most abundant beetles in the field. Bionomics, food specialization, temperature requirements and size group were assigned for 25 most common species. These traits determine the occurrence of staphylinid beetles in the field, the food sources they could utilize and thus also their likely contact with the Cry3Bb1 toxin. Statistical analysis of activity abundance, Rao indices and multivariate analysis of distribution of particular categories of functional traits in the field showed negligible effects of the experimental treatments, including the GM maize, upon the staphylinid community. Staphylinid beetles represent a considerably diverse part of epigeic field fauna with wide food specialization; these features render them suitable for the assessment of environmental safety of GM insect protected maize. However, the availability of prey and the presence of particular staphylinid species and their abundance are highly variable; this complicates the interpretation of the results.
Mathur, Chandni; Kathuria, Pooran C.; Dahiya, Pushpa; Singh, Anand B.
Background Genetically modified, (GM) crops with potential allergens must be evaluated for safety and endogenous IgE binding pattern compared to native variety, prior to market release. Objective To compare endogenous IgE binding proteins of three GM maize seeds containing Cry 1Ab,1Ac,1C transgenic proteins with non GM maize. Methods An integrated approach of in silico & in vitro methods was employed. Cry proteins were tested for presence of allergen sequence by FASTA in allergen databases. Biochemical assays for maize extracts were performed. Specific IgE (sIgE) and Immunoblot using food sensitized patients sera (n = 39) to non GM and GM maize antigens was performed. Results In silico approaches, confirmed for non sequence similarity of stated transgenic proteins in allergen databases. An insignificant (p> 0.05) variation in protein content between GM and non GM maize was observed. Simulated Gastric Fluid (SGF) revealed reduced number of stable protein fractions in GM then non GM maize which might be due to shift of constituent protein expression. Specific IgE values from patients showed insignificant difference in non GM and GM maize extracts. Five maize sensitized cases, recognized same 7 protein fractions of 88-28 kD as IgE bindng in both GM and non-GM maize, signifying absence of variation. Four of the reported IgE binding proteins were also found to be stable by SGF. Conclusion Cry proteins did not indicate any significant similarity of >35% in allergen databases. Immunoassays also did not identify appreciable differences in endogenous IgE binding in GM and non GM maize. PMID:25706412
Yang, Litao; Guo, Jinchao; Pan, Aihu; Zhang, Haibo; Zhang, Kewei; Wang, Zhengming; Zhang, Dabing
With the development of genetically modified organism (GMO) detection techniques, the Polymerase Chain Reaction (PCR) technique has been the mainstay for GMO detection, and real-time PCR is the most effective and important method for GMO quantification. An event-specific detection strategy based on the unique and specific integration junction sequences between the host plant genome DNA and the integrated gene is being developed for its high specificity. This study establishes the event-specific detection methods for TC1507 and CBH351 maizes. In addition, the event-specific TaqMan real-time PCR detection methods for another seven GM maize events (Bt11, Bt176, GA21, MON810, MON863, NK603, and T25) were systematically optimized and developed. In these PCR assays, the fluorescent quencher, TAMRA, was dyed on the T-base of the probe at the internal position to improve the intensity of the fluorescent signal. To overcome the difficulties in obtaining the certified reference materials of these GM maizes, one novel standard reference molecule containing all nine specific integration junction sequences of these GM maizes and the maize endogenous reference gene, zSSIIb, was constructed and used for quantitative analysis. The limits of detection of these methods were 20 copies for these different GM maizes, the limits of quantitation were about 20 copies, and the dynamic ranges for quantification were from 0.05 to 100% in 100 ng of DNA template. Furthermore, nine groups of the mixed maize samples of these nine GM maize events were quantitatively analyzed to evaluate the accuracy and precision. The accuracy expressed as bias varied from 0.67 to 28.00% for the nine tested groups of GM maize samples, and the precision expressed as relative standard deviations was from 0.83 to 26.20%. All of these indicated that the established event-specific real-time PCR detection systems and the reference molecule in this study are suitable for the identification and quantification of these GM
Wiedemann, S; Gürtler, P; Albrecht, C
Rumen-cannulated cows (n = 4) were fed successively silage made from either conventional or genetically modified (GM) maize. Results revealed no effects of GM maize on the dynamics of six ruminal bacterial strains (investigated by real-time PCR) compared to the conventional maize silage.
Ohgiya, Yoko; Sakai, Masaaki; Miyashita, Taeko; Yano, Koichi
Genetically modified maize MON863 (MON863), which has passed a safety examination in Japan, is commercially cultivated in the United States as a food and a resource for fuel. Maize is an anemophilous flower, which easily hybridizes. However, an official method for quantifying the content of MON863 has not been provided yet in Japan. We here examined MON863 contamination in maize-processed foods that had no labeling indicating of the use of genetically modified maize.From March 2006 to July 2008, we purchased 20 frozen maize products, 8 maize powder products, 7 canned maize products and 4 other maize processed foods. Three primer pairs named MON 863 primer, MON863-1, and M3/M4 for MON863-specific integrated cassette were used for qualitative polymerase chain reaction (PCR). A primer pair "SSIIb-3" for starch synthase gene was used to confirm the quality of extracted DNA. The starch synthase gene was detected in all samples. In qualitative tests, the MON863-specific fragments were detected in 7 (18%) maize powder products out of the 39 processed foods with all the three primer pairs.We concluded that various maize processed foods on the market were contaminated with MON863. It is important to accumulate further information on MON863 contamination in maize-processed foods that have no label indication of the use of genetically modified maize.
Galeano, Pablo; Debat, Claudio Martínez; Ruibal, Fabiana; Fraguas, Laura Franco; Galván, Guillermo A
The cultivation of genetically modified (GM) Bt maize (Zea mays L.) events MON810 and Bt11 is permitted in Uruguay. Local regulations specify that 10% of the crop should be a non-GM cultivar as refuge area for biodiversity, and the distance from other non-GM maize crops should be more than 250 m in order to avoid cross-pollination. However, the degree of cross-fertilization between maize crops in Uruguay is unknown. The level of adventitious presence of GM material in non-GM crops is a relevant issue for organic farming, in situ conservation of genetic resources and seed production. In the research reported here, the occurrence and frequency of cross-fertilization between commercial GM and non-GM maize crops in Uruguay was assessed. The methodology comprised field sampling and detection using DAS-ELISA and PCR. Five field-pair cases where GM maize crops were grown near non-GM maize crops were identified. These cases had the potential to cross-fertilize considering the distance between crops and the similarity of the sowing dates. Adventitious presence of GM material in the offspring of non-GM crops was found in three of the five cases. Adventitious presence of event MON810 or Bt11 in non-GM maize, which were distinguished using specific primers, matched the events in the putative sources of transgenic pollen. Percentages of transgenic seedlings in the offspring of the non-GM crops were estimated as 0.56%, 0.83% and 0.13% for three sampling sites with distances of respectively 40, 100 and 330 m from the GM crops. This is a first indication that adventitious presence of transgenes in non-GM maize crops will occur in Uruguay if isolation by distance and/or time is not provided. These findings contribute to the evaluation of the applicability of the "regulated coexistence policy" in Uruguay.
Primavesi, Lucia F; Wu, Huixia; Mudd, Elisabeth A; Day, Anil; Jones, Huw D
The ability to target marker proteins to specific subcellular compartments is a powerful research tool to study the structure and development of organelles. Here transit sequences from nuclear-encoded, plastid proteins, namely rice FtsZ, maize non-photosynthetic ferredoxin III (FdIII) and the small subunit of RubisCO were used to target a modified synthetic GFP (S65G, S72A) to plastids. The localisations of the fusion proteins expressed in transgenic wheat plants and under the control of the rice actin promoter were compared to an untargeted GFP control. GFP fluorescence was localised to non-green plastids in pollen, roots and seed endosperm and detected in isolated leaf chloroplasts using a GFP-specific antibody. Transit peptides appeared to influence the relative fluorescence intensities of plastids in different tissues. This is consistent with differential targeting and/or turnover of GFP fusion proteins in different plastid types. Replacement of GFP sequences with alternative coding regions enables immediate applications of our vectors for academic research and commercial applications.
Akiyama, Hiroshi; Watanabe, Takahiro; Wakabayashi, Kaoru; Nakade, Shinsuke; Yasui, Shuji; Sakata, Kozue; Chiba, Ryoko; Spiegelhalter, Frank; Hino, Akihiro; Maitani, Tamio
Various countries have established regulations that stipulate the labeling of agricultural commodities, feed, and food products that contain or are made from genetically modified (GM) material or that contain adventitious GM material in amounts that exceed certain threshold levels. While regulations in some countries refer to GM material on a weight per weight (w/w) percentage, the currently applied detection methods do not directly measure the w/w percentage of the GM material. Depending on the particular method and the sample matrix it is applied to, the conversion of analytical results to a w/w percentage is challenging or not possible. The first rapid PCR system for GM maize detection on a single kernel basis has been developed. The equipment for the grinding of individual kernels and a silica membrane-based 96-well DNA extraction kit were both significantly revised and optimized for this particular purpose, respectively. We developed a multiplex real-time PCR method for the rapid quantification of GM DNA sequences in the obtained DNA solutions. In addition, a multiplex qualitative PCR detection method allows for the simultaneous detection of different GM maize traits in each kernel and thereby for identification of individual kernels that contain a combination of two or more GM traits. Especially for grain samples that potentially contain combined-trait GM maize kernels, the proposed methods can deliver informative results in a rapid, precise, and reliable manner.
Sheehan, Moira J; Farmer, Phyllis R; Brutnell, Thomas P
To begin the study of phytochrome signaling in maize, we have cloned and characterized the phytochrome gene family from the inbred B73. Through DNA gel blot analysis of maize genomic DNA and BAC library screens, we show that the PhyA, PhyB, and PhyC genes are each duplicated once in the genome of maize. Each gene pair was positioned to homeologous regions of the genome using recombinant inbred mapping populations. These results strongly suggest that the duplication of the phytochrome gene family in maize arose as a consequence of an ancient tetraploidization in the maize ancestral lineage. Furthermore, sequencing of Phy genes directly from BAC clones indicates that there are six functional phytochrome genes in maize. Through Northern gel blot analysis and a semiquantitative reverse transcriptase polymerase chain reaction assay, we determined that all six phytochrome genes are transcribed in several seedling tissues. However, expression from PhyA1, PhyB1, and PhyC1 predominate in all seedling tissues examined. Dark-grown seedlings express higher levels of PhyA and PhyB than do light-grown plants but PhyC genes are expressed at similar levels under light and dark growth conditions. These results are discussed in relation to phytochrome gene regulation in model eudicots and monocots and in light of current genome sequencing efforts in maize. PMID:15280251
Elsanhoty, Rafaat M; Al-Turki, A I; Ramadan, Mohamed Fawzy
Qualitative and quantitative DNA-based methods were applied to detect genetically modified foods in samples from markets in the Kingdom of Saudi Arabia. Two hundred samples were collected from Al-Qassim, Riyadh, and Mahdina in 2009 and 2010. GMOScreen 35S and NOS test kits for the detection of genetically modified organism varieties in samples were used. The positive results obtained from GMOScreen 35S and NOS were identified using specific primer pairs. The results indicated that all rice samples gave negative results for the presence of 35S and NOS terminator. About 26 % of samples containing soybean were positive for 35S and NOS terminator and 44 % of samples containing maize were positive for the presence of 35S and/or NOS terminator. The results showed that 20.4 % of samples was positive for maize line Bt176, 8.8 % was positive for maize line Bt11, 8.8 % was positive for maize line T25, 5.9 % was positive for maize line MON 810, and 5.9 % was positive for StarLink maize. Twelve samples were shown to contain <3 % of genetically modified (GM) soy and 6 samples >10 % of GM soy. Four samples containing GM maize were shown to contain >5 % of GM maize MON 810. Four samples containing GM maize were shown to contain >1 % of StarLink maize. Establishing strong regulations and certified laboratories to monitor GM foods or crops in Saudi market is recommended.
Muula, Adamson S; Mfutso-Bengo, Joseph M
In 2001 and 2002, many countries in the Southern African Development Community (SADC) have suffered from severe food shortages resulting in an estimated 14 million people facing starvation due to inadequate quantities of the staple maize. The international community's response has been the donation of foodstuffs, including genetically modified maize. Reactions of the recipient countries of Zambia, Zimbabwe, and Malawi have been different. Zambia appealed to the donors not to send genetically modified maize, whereas Malawi accepted the maize donations. Malawi is currently facing many public health challenges because 10% of its 10-million population is HIV-positive, maternal mortality rate has almost doubled between 1992 and 2000, and there are also an estimated 1 million orphans due to HIV/AIDS. In the European Union, genetically modified maize falls under "Novel Foods" and its marketing and distribution are strictly regulated by law. This has never been the case in the southern African countries. In this article, we discuss the ethical challenges associated with genetically modified maize donations to southern Africa. Although genetically modified food offers a way to avoid many adverse effects of food shortages, we believe that some of the ethical questions of genetically modified food donations should be solved first, under the leadership of the donor countries and partnership of the developing countries. There are fears that consummation of genetically modified maize could have adverse health effects. These fears must be addressed if the confidence of developing countries in the donor community is to be maintained.
The objective of the performed investigations was to isolate pathogenic fungi from contaminated maize cobs, to assess the appearance of maize cob fusariosis and to determine grain contamination with deoxynivalenol in the cultivation of genetically modified maize containing a gene resistance against European corn borer (Ostrinia nubilalis Hbn) as well as selected non-modified cultivars. The plant material comprised the following genetically modified maize cultivar: DKC 3421 YG (MON 810) and non-modified cultivars obtained from Smolice Plant Breeding Ltd., IHAR Group: Junak (FAO 210-220), Prosna (FAO 220), SMH (FAO 230), Baca (FAO 220). Prior to harvesting, the occurrence of maize cob fusariosis was determined in the 89 (BBCH) developmental ripening stage. Microbiological assessment was carried out on grains selected from cobs characterized by various pathological symptoms. In 2008, a total of 133 isolates was obtained from the examined samples of infected maize plants, of which 51 isolates were species-identified, while in 2009, the total of 123 isolates were determined, of which 63 were species-identified. In both experimental years, the majority of isolates contained fungi from the Fusarium genus. The performed analysis of mean levels of cob contamination by fusarioses revealed that DKC 3421 YG (MON 810) and SMH (FAO 230) cultivars showed the smallest levels of contamination as well as the lowest percent of cob contamination per plant, while Junak (FAO 210-220) and Baca (FAO 220) cultivars were characterized by the highest degree of contamination. The lowest deoxynivalenol concentrations were determined in years 2008 and 2009 in the case of the DKC 3421 YG (MON 810) cultivar, whereas Prosna (FAO 220) cultivar was characterized by the highest deoxynivalenol concentration.
Matsuoka, T; Kuribara, H; Akiyama, H; Miura, H; Goda, Y; Kusakabe, Y; Isshiki, K; Toyoda, M; Hino, A
Seven lines of genetically modified (GM) maize have been authorized in Japan as foods and feeds imported from the USA. We improved a multiplex PCR method described in the previous report in order to distinguish the five lines of GM maize. Genomic DNA was extracted from GM maize with a silica spin column kit, which could reduce experimental time and improve safety in the laboratory and potentially in the environment. We sequenced recombinant DNA (r-DNA) introduced into GM maize, and re-designed new primer pairs to increase the specificity of PCR to distinguish five lines of GM maize by multiplex PCR. A primer pair for the maize intrinsic zein gene (Ze1) was also designed to confirm the presence of amplifiable maize DNA. The lengths of PCR products using these six primer pairs were different. The Ze1 and the r-DNAs from the five lines of GM maize were qualitatively detected in one tube. The specific PCR bands were distinguishable from each other on the basis of the expected length. The r-DNA could be detected from maize samples containing 0.5% of each of the five lines of GM maize. The sensitivity would be acceptable to secure the verification of non-GMO materials and to monitor the reliability of the labeling system.
Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari
This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control.
Zurbrügg, Corinne; Hönemann, Linda; Meissle, Michael; Romeis, Jörg; Nentwig, Wolfgang
The cultivation of genetically modified Bt maize has raised environmental concerns, as large amounts of plant residues remain in the field and may negatively impact the soil ecosystem. In a field experiment, decomposition of leaf residues from three genetically modified (two expressing the Cry1Ab, one the Cry3Bb1 protein) and six non-transgenic hybrids (the three corresponding non-transformed near-isolines and three conventional hybrids) was investigated using litterbags. To elucidate the mechanisms that cause differences in plant decomposition, structural plant components (i.e., C:N ratio, lignin, cellulose, hemicellulose) were examined. Furthermore, Cry1Ab and Cry3Bb1 protein concentrations in maize leaf residues were measured from harvest to the next growing season. While leaf residue decomposition in transgenic and non-transgenic plants was similar, differences among conventional cultivars were evident. Similarly, plant components among conventional hybrids differed more than between transgenic and non-transgenic hybrids. Moreover, differences in senescent plant material collected directly from plants were larger than after exposure to soil for 5 months. While the concentration of Cry3Bb1 was higher in senescent maize leaves than that of Cry1Ab, degradation was faster, indicating that Cry3Bb1 has a shorter persistence in plant residues. As decomposition patterns of Bt-transgenic maize were shown to be well within the range of common conventional hybrids, there is no indication of ecologically relevant, adverse effects on the activity of the decomposer community.
Falcone Ferreyra, María Lorena; Casas, María Isabel; Questa, Julia Irene; Herrera, Andrea Lorena; DeBlasio, Stacy; Wang, Jing; Jackson, David; Grotewold, Erich; Casati, Paula
Flavonoids are specialized compounds widely distributed and with diverse functions throughout the plant kingdom and with several benefits for human health. In particular, flavonols, synthesized by flavonol synthase (FLS), protect plants against UV-B radiation and are essential for male fertility in maize and other plants. We have recently characterized a UV-B inducible ZmFLS1, corresponding to the first to be described in monocot plants. Interestingly, the new assembly of the B73 maize genome revealed the presence of a second putative FLS gene (ZmFLS2), with very high identity with ZmFLS1. ZmFLSs expression was analyzed in different maize tissues, and by combining electrophoretic mobility shift assays and transient expression experiments, we show that both genes are direct targets of anthocyanin (C1/PL1 + R/B) and 3-deoxy flavonoid (P1) transcriptional regulators. ZmFLS expression analyses show higher levels of both transcripts in high altitude landraces than inbred lines, and both genes are regulated by UV-B radiation in all lines analyzed. Moreover, the high sequence conservation of the ZmFLS promoters between maize lines suggests that the differences observed in ZmFLS expression are due to allelic variations in the transcription factors that regulate their activities. Finally, we generated pFLS1::FLS1-RFP transgenic plants and analyzed ZmFLS1 expression in different maize tissues; we found that this enzyme is localized in the ER and the perinuclear region. PMID:22654889
Johnston, Robyn; Candela, Héctor; Hake, Sarah; Foster, Toshi
Plant lateral organs, such as leaves, have three primary axes of growth-proximal-distal, medial--lateral and adaxial-abaxial (dorsal-ventral). Although most leaves are planar, modified leaf forms, such as the bikeeled grass prophyll, can be found in nature. A detailed examination of normal prophyll development indicates that polarity is established differently in the keels than in other parts of the prophyll. Analysis of the maize HD-ZIPIII gene rolled leaf1 (rld1) suggests that altered expression patterns are responsible for keel outgrowth. Recessive mutations in the maize (Zea mays) KANADI (KAN) gene milkweed pod1 (mwp1), which promotes abaxial cell identity, strongly affect development of the prophyll and silks (fused carpels). The prophyll is reduced to two unfused midribs and the silks are narrow and misshapen. Our data indicate that the prophyll and other fused organs are particularly sensitive to disruptions in adaxial-abaxial polarity. In addition, lateral and proximal-distal growth of most lateral organs is reduced in the mwp1-R mutant, supporting a role for the adaxial-abaxial boundary in promoting growth along both axes. We propose that the adaxial-abaxial patterning mechanism has been co-opted during evolution to generate diverse organ morphologies.
Lara-Núñez, Aurora; García-Ayala, Brendy B; Garza-Aguilar, Sara M; Flores-Sánchez, Jesús; Sánchez-Camargo, Victor A; Bravo-Alberto, Carlos E; Vázquez-Santana, Sonia; Vázquez-Ramos, Jorge M
Glucose and sucrose play a dual role: as carbon and energy sources and as signaling molecules. In order to address the impact that sugars may have on maize seeds during germination, embryo axes were incubated with or without either of the two sugars. Expression of key cell cycle markers and protein abundance, cell patterning and de novo DNA synthesis in root meristem zones were analyzed. Embryo axes without added sugars in imbibition medium were unable to grow after 7 days; in sucrose, embryo axes developed seminal and primary roots with numerous root hairs, whereas in glucose axes showed a twisted morphology, no root hair formation but callus-like structures on adventitious and primary seminal roots. More and smaller cells were observed with glucose treatment in root apical meristems. de novo DNA synthesis was stimulated more by glucose than by sucrose. At 24 h of imbibition, expression of ZmCycD2;2a and ZmCycD4;2 was increased by sucrose and reduced by glucose. CDKA1;1 and CDKA2;1 expression was stimulated equally by both sugars. Protein abundance patterns were modified by sugars: ZmCycD2 showed peaks on glucose at 12 and 36 h of imbibition whereas sucrose promoted ZmCycD3 protein accumulation. In presence of glucose ZmCycD3, ZmCycD4 and ZmCycD6 protein abundance was reduced after 24 h. Finally, both sugars stimulated ZmCDKA protein accumulation but at different times. Overall, even though glucose appears to act as a stronger mitogen stimulator, sucrose stimulated the expression of more cell cycle markers during germination. This work provides evidence of a differential response of cell cycle markers to sucrose and glucose during maize germination that may affect the developmental program during plantlet establishment.
Duggan, Paula S; Chambers, Philip A; Heritage, John; Michael Forbes, J
The polymerase chain reaction (PCR) technique was used to investigate the fate of a transgene in the rumen of sheep fed silage and maize grains from an insect-resistant maize line. A 1914-bp DNA fragment containing the entire coding region of the synthetic cryIA(b) gene was still amplifiable from rumen fluid sampled 5 h after feeding maize grains. The same target sequence, however, could not be amplified from rumen fluid sampled from sheep fed silage prepared from the genetically modified maize line. PCR amplification of a shorter (211-bp), yet still highly specific, target sequence was possible with rumen fluid sampled up to 3 and 24 h after feeding silage and maize grains, respectively. These findings indicate that intact transgenes from silage are unlikely to survive significantly in the rumen since a DNA sequence 211-bp long is very unlikely to transmit genetic information. By contrast, DNA in maize grains persists for a significant time and may, therefore, provide a source of transforming DNA in the rumen. In addition, we have examined the biological activity of plasmid DNA that had previously been exposed to the ovine oral cavity. Plasmid extracted from saliva sampled after incubation for 8 min was still capable of transforming competent Escherichia coli to kanamycin resistance, implying that DNA released from the diet within the mouth may retain sufficient biological activity for the transformation of competent oral bacteria.
Background Profiling technologies allow the simultaneous measurement and comparison of thousands of cell components without prior knowledge of their identity. In the present study, we used two-dimensional gel electrophoresis combined with mass spectrometry to evaluate protein expression of Brazilian genetically modified maize hybrid grown under different agroecosystems conditions. To this effect, leaf samples were subjected to comparative analysis using the near-isogenic non-GM hybrid as the comparator. Results In the first stage of the analysis, the main sources of variation in the dataset were identified by using Principal Components Analysis which correlated most of the variation to the different agroecosystems conditions. Comparative analysis within each field revealed a total of thirty two differentially expressed proteins between GM and non-GM samples that were identified and their molecular functions were mainly assigned to carbohydrate and energy metabolism, genetic information processing and stress response. Conclusions To the best of our knowledge this study represents the first evidence of protein identities with differentially expressed isoforms in Brazilian MON810 genetic background hybrid grown under field conditions. As global databases on outputs from “omics” analysis become available, these could provide a highly desirable benchmark for safety assessments. PMID:24304660
Plants contain defense mechanisms that prevent infection by most fungi. Some specialized fungi have the ability to overcome plant defenses. The Zea mays (maize) seed chitinase ChitA has been previously reported as an antifungal protein. Here we report that ChitA is converted to a modified form by...
In commercial maize, there are at least two different alleles of the chiA gene that encode alloforms of ChitA chitinase, a protein that is abundant in developing seed. Both known alloforms are modified by Bz-cmp, a protein secreted by the fungal pathogen Bipolaris zeicola. One alloform (ChitA-B73) i...
Bai, Yanjie; Kaufman, Rhett C; Wilson, Jeff D; Shi, Yong-Cheng
Octenylsuccinic anhydride (OSA)-modified starches with a low (0.018) and high (0.092) degree of substitution (DS) were prepared from granular native waxy maize starch in aqueous slurry. The position of OS substituents along the starch chains was investigated by enzyme hydrolysis followed by chromatographic analysis. Native starch and two OS starches with a low and high DS had β-limit values of 55.9%, 52.8%, and 34.4%, respectively. The weight-average molecular weight of the β-limit dextrin from the OS starch with a low DS was close to that of the β-limit dextrin from native starch but lower than that of the β-limit dextrin from the OS starch with a high DS. Debranching of OS starches was incomplete compared with native starch. OS groups in the OS starch with a low DS were located on the repeat units near the branching points, whereas the OS substituents in the OS starch with a high DS occurred both near the branching points and the non-reducing ends.
NemÅ£anu, M. R.; Minea, R.; Kahraman, K.; Koksel, H.; Ng, P. K. W.; Popescu, M. I.; Mitru, E.
Maize starch is a versatile biopolymer with a wide field of applications (e.g. foods, pharmaceutical products, adhesives, etc.). Nowadays there is a continuous and intensive search for new methods and techniques to modify its functional properties due to the fact that native form of starch may exhibit some disadvantages in certain applications. Radiation technology is frequently used to change the properties of different polymeric materials. Thus, the goal of the work is to discuss the application of accelerated electron beams on maize starch in the view of changing some of its functional properties. Maize starch has been irradiated with doses up to 52.15 kGy by using electron beam technology and the modifications of differential scanning calorimetry (DSC) and pasting characteristics, paste clarity, freezing and thawing stability as well as colorimetric characteristics have been investigated. The results of the study revealed that the measured properties can be modified by electron beam treatment and, therefore, this method can be an efficient and ecological alternative to obtain modified maize starch.
Liu, Hongjun; Shi, Junpeng; Sun, Chuanlong; Gong, Hao; Fan, Xingming; Qiu, Fazhan; Huang, Xuehui; Feng, Qi; Zheng, Xixi; Yuan, Ningning; Li, Changsheng; Zhang, Zhiyong; Deng, Yiting; Wang, Jiechen; Pan, Guangtang; Han, Bin; Lai, Jinsheng; Wu, Yongrui
The maize opaque2 (o2) mutant has a high nutritional value but it develops a chalky endosperm that limits its practical use. Genetic selection for o2 modifiers can convert the normally chalky endosperm of the mutant into a hard, vitreous phenotype, yielding what is known as quality protein maize (QPM). Previous studies have shown that enhanced expression of 27-kDa γ-zein in QPM is essential for endosperm modification. Taking advantage of genome-wide association study analysis of a natural population, linkage mapping analysis of a recombinant inbred line population, and map-based cloning, we identified a quantitative trait locus (qγ27) affecting expression of 27-kDa γ-zein. qγ27 was mapped to the same region as the major o2 modifier (o2 modifier1) on chromosome 7 near the 27-kDa γ-zein locus. qγ27 resulted from a 15.26-kb duplication at the 27-kDa γ-zein locus, which increases the level of gene expression. This duplication occurred before maize domestication; however, the gene structure of qγ27 appears to be unstable and the DNA rearrangement frequently occurs at this locus. Because enhanced expression of 27-kDa γ-zein is critical for endosperm modification in QPM, qγ27 is expected to be under artificial selection. This discovery provides a useful molecular marker that can be used to accelerate QPM breeding.
Polidoros, A N; Scandalios, J G
The Cat3 gene of maize exhibits a transcriptionally regulated circadian rhythm. In the present study we examined the following: (1) the extent of the circadian Cat3 expression between maize genotypes of diverse origin; (2) the functional significance of a Tourist transposable element located in the Cat3 promoter of the inbred line W64A, which harbors putative regulatory elements (GATA repeat, CCAAT boxes) shown to be involved in the light induction and circadian regulation of the Arabidopsis CAB2, as well as other plant genes; and (3) aspects of the physiological role of CAT-3 in maize metabolism. Results confirm that the circadian Cat3 expression is a general phenomenon in maize. Regulation of Cat3 gene expression is not dependent on the presence of the Tourist element in the promoter of the gene nor on the presence of motifs similar to those found significant in the circadian expression of the Arabidopsis CAB2 gene. Structural diversity was revealed in the Cat3 promoters of maize genotypes of diverse origins. However, highly conserved regions with putative regulatory motifs were identified. Relevance of the conserved regions to the circadian regulation of the gene is discussed. Possible physiological roles of CAT-3 are suggested. PMID:9584112
Huang, Ling; Xiang, Jie; Liu, Jiazhou; Rong, Tingzhao; Wang, Jing; Lu, Yanli; Tang, Qilin; Wen, Wen; Cao, Moju
Cytoplasmic male sterility (CMS)-C is one of the most attractive sources of male sterility in the production of hybrid maize. However, the abortion mechanism of CMS-C is currently unknown. The major aim of this work was to characterize the expression of genes and proteins during pollen abortion. The materials assayed included CMS-C line C48-2, its maintainer line N48-2, and fertile F(1) (C48-2 × 18 white). A total of 20 unique genes and 25 proteins were identified by suppression subtractive hybridization and 2-D electrophoresis, respectively. Most of the genes and proteins identified are closely related to energy metabolism, stress responses, molecular chaperones, and cell death, which are generally considered to be essential to pollen development. Based on the function of these identified genes and proteins, reactive oxygen species in isolated mitochondria and DNA fragments were analyzed. The results from this study indicate that the oxidative stress which was associated with the specific expression patterns of some genes may be the physiological cause for the abortion of premature microspores in the maize CMS-C line.
A detailed examination of normal prophyll development indicates that polarity is established differently in the keels than in other parts of the prophyll. Analysis of the maize HD-ZIPIII gene rolled leaf1 (rld1) suggests that altered expression patterns are responsible for keel outgrowth. Recessive ...
Rabiei, Maryam; Mehdizadeh, Mehrangiz; Rastegar, Hossein; Vahidi, Hossein; Alebouyeh, Mahmoud
Detection of genetically modified organisms (GMOs) in food is an important issue for all the subjects involved in food control and customer's right. Due to the increasing number of GMOs imported to Iran during the past few years, it has become necessary to screen the products in order to determine the identity of the consumed daily foodstuffs. In this study, following the extraction of genomic DNA from processed foods sold commercially in Iran, qualitative PCR was performed to detect genetically modified maize. The recombinant DNA target sequences were detected with primers highly specific for each investigated transgene such as CaMV35s gene, Bt-11, MON810 and Bt-176 separately. Based on the gel electrophoresis results, Bt- 11 and MON810 events were detected in some maize samples, while, in none of them Bt- 176 modified gene was detected. For the first time, the results demonstrate the presence of genetically modified maize in Iranian food products, reinforcing the need for the development of labeling system and valid quantitative methods in routine analyses.
Mumm, Rita H
Plant breeding for crop genetic improvement involves the cycle of creating genetic diversity and exploiting that diversity to derive an improved cultivar with outstanding performance for specific traits of interest. Genetic modification through transformation essentially expands the genepool to facilitate access to genes otherwise not available through crossing. Transgenic events are defined by the DNA sequence that has been incorporated into the target genome and the specific point(s) of insertion. In the development of a new transgenic trait, typically many events are generated and evaluated with the aim of identifying one exhibiting consistent trait expression at or above specified thresholds, stable inheritance, and the absence of any negative effects. With transgenic traits for maize, once commercial candidates have been identified, these events are introgressed into elite lines, often through the use of molecular markers that can accelerate the breeding process and aid in producing a quality conversion. Converted elite lines are yield-tested to ensure performance equivalency with their unconverted counterparts. Finally, before commercial sale of seed, quality control monitoring is conducted to ensure event identity and purity and the absence of any unintended events. This monitoring complements other quality control measures to confirm seed viability and line/hybrid purity and uniformity in seed treatments, all in an effort to ensure customer satisfaction and to comply with governmental regulations. Thus, genetically modified (GM) cultivars are subject to significant testing and auditing prior to seed sale and distribution to farmers, more testing and auditing than with non-GM cultivars.
Xu, Junyi; Zheng, Qiuyue; Yu, Ling; Liu, Ran; Zhao, Xin; Wang, Gang; Wang, Qinghua; Cao, Jijuan
The loop-mediated isothermal amplification (LAMP) assay indicates a potential and valuable means for genetically modified organism (GMO) detection especially for its rapidity, simplicity, and low cost. We developed and evaluated the specificity and sensitivity of the LAMP method for rapid detection of the genetically modified (GM) maize T25. A set of six specific primers was successfully designed to recognize six distinct sequences on the target gene, including a pair of inner primers, a pair of outer primers, and a pair of loop primers. The optimum reaction temperature and time were verified to be 65°C and 45 min, respectively. The detection limit of this LAMP assay was 5 g kg(-1) GMO component. Comparative experiments showed that the LAMP assay was a simple, rapid, accurate, and specific method for detecting the GM maize T25.
Bánáti, Hajnalka; Darvas, Béla; Fehér-Tóth, Szilvia; Czéh, Árpád; Székács, András
Levels of mycotoxins produced by Fusarium species in genetically modified (GM) and near-isogenic maize, were determined using multi-analyte, microbead-based flow immunocytometry with fluorescence detection, for the parallel quantitative determination of fumonisin B1, deoxynivalenol, zearalenone, T-2, ochratoxin A, and aflatoxin B1. Maize varieties included the genetic events MON 810 and DAS-59122-7, and their isogenic counterparts. Cobs were artificially infested by F. verticillioides and F. proliferatum conidia, and contained F. graminearum and F. sporotrichoides natural infestation. The production of fumonisin B1 and deoxynivalenol was substantially affected in GM maize lines: F. verticillioides, with the addition of F. graminearum and F. sporotrichoides, produced significantly lower levels of fumonisin B1 (~300 mg·kg−1) in DAS-59122-7 than in its isogenic line (~580 mg·kg−1), while F. proliferatum, in addition to F. graminearum and F. sporotrichoides, produced significantly higher levels of deoxynivalenol (~18 mg·kg−1) in MON 810 than in its isogenic line (~5 mg·kg−1). Fusarium verticillioides, with F. graminearum and F. sporotrichoides, produced lower amounts of deoxynivalenol and zearalenone than F. proliferatum, with F. graminearum and F. sporotrichoides. T-2 toxin production remained unchanged when considering the maize variety. The results demonstrate the utility of the Fungi-Plex™ quantitative flow immunocytometry method, applied for the high throughput parallel determination of the target mycotoxins. PMID:28241411
Pophaly, Saurabh D; Tellier, Aurélien
The maize ancestor experienced a recent whole-genome duplication (WGD) followed by gene erosion which generated two subgenomes, the dominant subgenome (maize1) experiencing fewer deletions than maize2. We take advantage of available extensive polymorphism and gene expression data in maize to study purifying selection and gene expression divergence between WGD retained paralog pairs. We first report a strong correlation in nucleotide diversity between duplicate pairs, except for upstream regions. We then show that maize1 genes are under stronger purifying selection than maize2. WGD retained genes have higher gene dosage and biased Gene Ontologies consistent with previous studies. The relative gene expression of paralogs across tissues demonstrates that 98% of duplicate pairs have either subfunctionalized in a tissuewise manner or have diverged consistently in their expression thereby preventing functional complementation. Tissuewise subfunctionalization seems to be a hallmark of transcription factors, whereas consistent repression occurs for macromolecular complexes. We show that dominant gene expression is a strong determinant of the strength of purifying selection, explaining the inferred stronger negative selection on maize1 genes. We propose a novel expression-based classification of duplicates which is more robust to explain observed polymorphism patterns than the subgenome location. Finally, upstream regions of repressed genes exhibit an enrichment in transposable elements which indicates a possible mechanism for expression divergence.
Maize mutant bf-1 was one of a series of maize mutants generated by radiation from the Bikini Atoll atomic bomb test in 1946. It is characterized by blue fluorescence in seedlings and anthers under ultraviolet illumination and by mutant plants giving off a characteristic grape-like odor due to the ...
Wu, Y.; Meeley, R. B.; Cosgrove, D. J.
Expansins comprise a multigene family of proteins in maize (Zea mays). We isolated and characterized 13 different maize expansin cDNAs, five of which are alpha-expansins and eight of which are beta-expansins. This paper presents an analysis of these 13 expansins, as well as an expression analysis by northern blotting with materials from young and mature maize plants. Some expansins were expressed in restricted regions, such as the beta-expansins ExpB1 (specifically expressed in maize pollen) and ExpB4 (expressed principally in young husks). Other expansins such as alpha-expansin Exp1 and beta-expansin ExpB2 were expressed in several organs. The expression of yet a third group was not detected in the selected organs and tissues. An analysis of expansin sequences from the maize expressed sequence tag collection is also presented. Our results indicate that expansin genes may have general, overlapping expression in some instances, whereas in other cases the expression may be highly specific and limited to a single organ or cell type. In contrast to the situation in Arabidopsis, beta-expansins in maize seem to be more numerous and more highly expressed than are alpha-expansins. The results support the concept that beta-expansins multiplied and evolved special functions in the grasses.
Turkec, Aydin; Kazan, Hande; Karacanli, Burçin; Lucas, Stuart J
In this paper, DNA extraction methods have been evaluated to detect the presence of genetically modified organisms (GMOs) in maize food and feed products commercialised in Turkey. All the extraction methods tested performed well for the majority of maize foods and feed products analysed. However, the highest DNA content was achieved by the Wizard, Genespin or the CTAB method, all of which produced optimal DNA yield and purity for different maize food and feed products. The samples were then screened for the presence of GM elements, along with certified reference materials. Of the food and feed samples, 8 % tested positive for the presence of one GM element (NOS terminator), of which half (4 % of the total) also contained a second element (the Cauliflower Mosaic Virus 35S promoter). The results obtained herein clearly demonstrate the presence of GM maize in the Turkish market, and that the Foodproof GMO Screening Kit provides reliable screening of maize food and feed products.
Paternò, Annalisa; Marchesi, Ugo; Gatto, Francesco; Verginelli, Daniela; Quarchioni, Cinzia; Fusco, Cristiana; Zepparoni, Alessia; Amaddeo, Demetrio; Ciabatti, Ilaria
The comparison of five real-time polymerase chain reaction (PCR) methods targeted at maize ( Zea mays ) endogenous sequences is reported. PCR targets were the alcohol dehydrogenase (adh) gene for three methods and high-mobility group (hmg) gene for the other two. The five real-time PCR methods have been checked under repeatability conditions at several dilution levels on both pooled DNA template from several genetically modified (GM) maize certified reference materials (CRMs) and single CRM DNA extracts. Slopes and R(2) coefficients of all of the curves obtained from the adopted regression model were compared within the same method and among all of the five methods, and the limit of detection and limit of quantitation were analyzed for each PCR system. Furthermore, method equivalency was evaluated on the basis of the ability to estimate the target haploid genome copy number at each concentration level. Results indicated that, among the five methods tested, one of the hmg-targeted PCR systems can be considered equivalent to the others but shows the best regression parameters and a higher repeteability along the dilution range. Thereby, it is proposed as a valid module to be coupled to different event-specific real-time PCR for maize genetically modified organism (GMO) quantitation. The resulting practicability improvement on the analytical control of GMOs is discussed.
Chen, Yuxiang; Zhang, Yufen; Zhang, Quanguo; Xu, Lixin; Li, Ran; Luo, Xiaopei; Zhang, Xin; Tong, Jin
In the present study, maize stover was vermicomposted with the epigeic earthworm Eisenia fetida. The results showed that, during vermicomposting process, the earthworms promoted decomposition of maize stover. Analysis of microbial communities of the vermicompost by high-throughput pyrosequencing showed more complex bacterial community structure in the substrate treated by the earthworms than that in the control group. The dominant microbial genera in the treatment with the earthworms were Pseudoxanthomonas, Pseudomonas, Arthrobacter, Streptomyces, Cryptococcus, Guehomyces, and Mucor. Compared to the control group, the relative abundance of lignocellulose degradation microorganisms increased. The results indicated that the earthworms modified the structure of microbial communities during vermicomposting process, activated the growth of lignocellulose degradation microorganisms, and triggered the lignocellulose decomposition.
Devos, Yann; Meihls, Lisa N; Kiss, József; Hibbard, Bruce E
Western corn rootworm (Diabrotica virgifera virgifera; WCR) is a major coleopteran maize pest in North America and the EU, and has traditionally been managed through crop rotation and broad-spectrum soil insecticides. Genetically modified Bt-maize offers an additional management tool for WCR and has been valuable in reducing insecticide use and increasing farm income. A concern is that the widespread, repeated, and exclusive deployment of the same Bt-maize transformation event will result in the rapid evolution of resistance in WCR. This publication explores the potential of WCR to evolve resistance to plant-produced Bt-toxins from the first generation of Diabrotica-active Bt-maize events (MON 863 and MON 88017, DAS-59122-7 and MIR604), and whether currently implemented risk management strategies to delay and monitor resistance evolution are appropriate. In twelve of the twelve artificial selection experiments reported, resistant WCR populations were yielded rapidly. Field-selected resistance of WCR to Cry3Bb1 is documented in some US maize growing areas, where an increasing number of cases of unexpected damage of WCR larvae to Bt-maize MON 88017 has been reported. Currently implemented insect resistance management measures for Bt-crops usually rely on the high dose/refuge (HDR) strategy. Evidence (including laboratory, greenhouse and field data) indicates that several conditions contributing to the success of the HDR strategy may not be met for the first generation of Bt-maize events and WCR: (1) the Bt-toxins are expressed heterogeneously at a low-to-moderate dose in roots; (2) resistance alleles may be present at a higher frequency than initially assumed; (3) WCR may mate in a non-random manner; (4) resistance traits could have non-recessive inheritance; and (5) fitness costs may not necessarily be associated with resistance evolution. However, caution must be exercised when extrapolating laboratory and greenhouse results to field conditions. Model predictions
Li, Ning; Zhang, Shujuan; Zhao, Yajie; Li, Bei; Zhang, Juren
Cereal crops accumulate starch in the seed endosperm as an energy reserve. ADP-glucose pyrophosphorylase (AGPase) plays a key role in regulating starch biosynthesis in cereal seeds. The AGPase in the maize endosperm is a heterotetramer of two small subunits, encoded by Brittle2 (Bt2) gene, and two large subunits, encoded by the Shrunken2 (Sh2) gene. The two genes (Bt2, Sh2) from maize were introduced into two elite maize inbred lines, solely and in tandem, and under the control of endosperm-specific promoters for over-expression. PCR, Southern blotting, and real-time RT-PCR analysis indicated that the transgenes were integrated into the genome of transgenic plants and were over-expressed in their progeny. The over-expression of either gene enhanced AGPase activity, seed weight and starch content compared with the WT, but the amounts were lower than plants with over-expression of both Bt2 and Sh2. Developing seeds from co-expression transgenic maize plants had higher cytoplasmic AGPase activity: the 100-grain weight increased 15% over the wild type (WT), and the starch content increased to over 74% compared with the WT of 65%. These results indicate that over-expression of the genes in transgenic maize plants could improve kernel traits. This report provides a feasible approach for increasing starch content and seed weight in maize.
Ocaña, Mireia Fernández; Fraser, Paul D; Patel, Raj K P; Halket, John M; Bramley, Peter M
The potential of protein fractionation hyphenated to mass spectrometry (MS) to detect and characterize the transgenic protein present in Roundup Ready soya and maize has been investigated. Genetically modified (GM) soya and maize contain the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene from Agrobacterium tumefaciens CP4, which confers resistance to the herbicide glyphosate. The GM soya and maize proteomes were fractionated by gel filtration, anion-exchange chromatography and sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) prior to MS. This facilitated detection of a tryptic peptide map of CP4 EPSPS by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS and nanoelectrospray ionization quadrupole time-of-flight (nanoESI-QTOF) MS. Subsequently, sequence information from the CP4 EPSPS tryptic peptides was obtained by nanoESI-QTOF MS/MS. The identification was accomplished in 0.9% GM soya seeds, which is the current EU threshold for food-labeling requirements.
Anthocyanin biosynthesis in maize protects tissues from biotic and abiotic stresses. Constitutive expression of the maize B1 and C1 genes, which induces anthocyanin biosynthesis, resulted in transgenic plants with varied phenotypes. Some colored leaves were substantially resistant to thrips damage...
Shou, Huixia; Bordallo, Patricia; Wang, Kan
Drought is one of the most important abiotic stresses affecting the productivity of maize. Previous studies have shown that expression of a mitogen-activated protein kinase kinase kinase (MAPKKK) gene activated an oxidative signal cascade and led to the tolerance of freezing, heat, and salinity stress in transgenic tobacco. To analyse the role of activation of oxidative stress signalling in improving drought tolerance in major crops, a tobacco MAPKKK (NPK1) was expressed constitutively in maize. Results show that NPK1 expression enhanced drought tolerance in transgenic maize. Under drought conditions, transgenic maize plants maintained significantly higher photosynthesis rates than did the non-transgenic control, suggesting that NPK1 induced a mechanism that protected photosynthesis machinery from dehydration damage. In addition, drought-stressed transgenic plants produced kernels with weights similar to those under well-watered conditions, while kernel weights of drought-stressed non-transgenic control plants were significantly reduced when compared with their non-stressed counterparts.
Bowersox, Karisa; Chopra, Surinder
Pericarp color 1 is a model system for the study of epigenetic gene regulation. It has more than 100 alleles that contribute to the color of the pericarp and cob glume of maize. Unstable factor for orange 1 (Ufo1) is a spontaneous dominant mutation that leads to a gain in pigmentation due to a decrease in methylation in p1 genes. This decrease in methylation of cytosine in the DNA leads to changes in chromatin structure. Finding the mechanism for this spontaneous mutation can lead to way of preventing the mutation increasing production colorless maize for food production. Through genotyping and phenotyping fine gene mapping, gene expression and whole genome profiling can be accomplished for plants with the Ufo1 mutation present.
El-Mesbahi, Mohamed Najib; Azcón, Rosario; Ruiz-Lozano, Juan Manuel; Aroca, Ricardo
It is well known that the arbuscular mycorrhizal (AM) symbiosis helps the host plant to overcome several abiotic stresses including drought. One of the mechanisms for this drought tolerance enhancement is the higher water uptake capacity of the mycorrhizal plants. However, the effects of the AM symbiosis on processes regulating root hydraulic properties of the host plant, such as root hydraulic conductivity and plasma membrane aquaporin gene expression, and protein abundance, are not well defined. Since it is known that K(+) status is modified by AM and that it regulates root hydraulic properties, it has been tested how plant K(+) status could modify the effects of the symbiosis on root hydraulic conductivity and plasma membrane aquaporin gene expression and protein abundance, using maize (Zea mays L.) plants and Glomus intraradices as a model. It was observed that the supply of extra K(+) increased root hydraulic conductivity only in AM plants. Also, the different pattern of plasma membrane aquaporin gene expression and protein abundance between AM and non-AM plants changed with the application of extra K(+). Thus, plant K(+) status could be one of the causes of the different observed effects of the AM symbiosis on root hydraulic properties. The present study also highlights the critical importance of AM fungal aquaporins in regulating root hydraulic properties of the host plant.
Liu, Hongjun; Shi, Junpeng; Sun, Chuanlong; Gong, Hao; Fan, Xingming; Qiu, Fazhan; Huang, Xuehui; Feng, Qi; Zheng, Xixi; Yuan, Ningning; Li, Changsheng; Zhang, Zhiyong; Deng, Yiting; Wang, Jiechen; Pan, Guangtang; Han, Bin; Lai, Jinsheng; Wu, Yongrui
The maize opaque2 (o2) mutant has a high nutritional value but it develops a chalky endosperm that limits its practical use. Genetic selection for o2 modifiers can convert the normally chalky endosperm of the mutant into a hard, vitreous phenotype, yielding what is known as quality protein maize (QPM). Previous studies have shown that enhanced expression of 27-kDa γ-zein in QPM is essential for endosperm modification. Taking advantage of genome-wide association study analysis of a natural population, linkage mapping analysis of a recombinant inbred line population, and map-based cloning, we identified a quantitative trait locus (qγ27) affecting expression of 27-kDa γ-zein. qγ27 was mapped to the same region as the major o2 modifier (o2 modifier1) on chromosome 7 near the 27-kDa γ-zein locus. qγ27 resulted from a 15.26-kb duplication at the 27-kDa γ-zein locus, which increases the level of gene expression. This duplication occurred before maize domestication; however, the gene structure of qγ27 appears to be unstable and the DNA rearrangement frequently occurs at this locus. Because enhanced expression of 27-kDa γ-zein is critical for endosperm modification in QPM, qγ27 is expected to be under artificial selection. This discovery provides a useful molecular marker that can be used to accelerate QPM breeding. PMID:27092004
Bakke-McKellep, A M; Sanden, M; Danieli, A; Acierno, R; Hemre, G-I; Maffia, M; Krogdahl, A
Physiological and health related responses to dietary inclusion of genetically modified (GM) full-fat soybean meal (Roundup Ready; GM-soy) and maize (MON810 Bt-maize; GM-maize), as well as non-parental, untransformed lines (nGM-soy and nGM-maize D2), were evaluated in farmed Atlantic salmon (Salmo salar L.) parr during the first 8 months of feeding. Significant effects of dietary GM presence were only found in intestinal Na+-dependent d-glucose uptake and SGLT1 protein level in the region pyloric caeca in which the highest values were found in the GM-soy, intermediate in the nGM-soy, and lowest in the standard FM fed groups. Data from this study confirm that GM soybeans (RRS) and maize (MON810) at inclusion levels of about 6% appear to be as safe as commercially available nGM soy and maize in diets for Atlantic salmon parr. Results from studies with higher inclusion levels and with non-modified, isogenic or near-isogenic parental lines as control groups are pending.
Zhao, Yanxin; Cai, Manjun; Zhang, Xiaobo; Li, Yurong; Zhang, Jianhua; Zhao, Hailiang; Kong, Fei; Zheng, Yonglian; Qiu, Fazhan
Plant mitochondrial transcription termination factor (mTERF) genes comprise a large family with important roles in regulating organelle gene expression. In this study, a comprehensive database search yielded 31 potential mTERF genes in maize (Zea mays L.) and most of them were targeted to mitochondria or chloroplasts. Maize mTERF were divided into nine main groups based on phylogenetic analysis, and group IX represented the mitochondria and species-specific clade that diverged from other groups. Tandem and segmental duplication both contributed to the expansion of the mTERF gene family in the maize genome. Comprehensive expression analysis of these genes, using microarray data and RNA-seq data, revealed that these genes exhibit a variety of expression patterns. Environmental stimulus experiments revealed differential up or down-regulation expression of maize mTERF genes in seedlings exposed to light/dark, salts and plant hormones, respectively, suggesting various important roles of maize mTERF genes in light acclimation and stress-related responses. These results will be useful for elucidating the roles of mTERF genes in the growth, development and stress response of maize. PMID:24718683
Benevenuto, Rafael Fonseca; Agapito-Tenfen, Sarah Zanon; Vilperte, Vinicius; Wikmark, Odd-Gunnar; van Rensburg, Peet Jansen; Nodari, Rubens Onofre
Some genetically modified (GM) plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA) analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses.
Benevenuto, Rafael Fonseca; Agapito-Tenfen, Sarah Zanon; Vilperte, Vinicius; Wikmark, Odd-Gunnar; van Rensburg, Peet Jansen; Nodari, Rubens Onofre
Some genetically modified (GM) plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA) analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses. PMID:28245233
Hasjim, Jovin; Jane, Jay-Lin
The objective of this study was to utilize extrusion cooking and hydrothermal treatment to produce resistant starch (RS) as an economical alternative to a batch-cooking process. A hydrothermal treatment (110 degrees C, 3 d) of batch-cooked and extruded starch samples facilitated propagation of heat-stable starch crystallites and increased the RS contents from 2.1% to 7.7% up to 17.4% determined using AOAC Method 991.43 for total dietary fiber. When starch samples were batch cooked and hydrothermally treated at a moisture content below 70%, acid-modified normal-maize starch (AMMS) produced a greater RS content than did native normal-maize starch (NMS). This was attributed to the partially hydrolyzed, smaller molecules in the AMMS, which had greater mobility and freedom than the larger molecules in the NMS. The RS contents of the batch-cooked and extruded AMMS products after the hydrothermal treatment were similar. A freezing treatment of the AMMS samples at -20 degrees C prior to the hydrothermal treatment did not increase the RS content. The DSC thermograms and the X-ray diffractograms showed that retrograded amylose and crystalline starch-lipid complex, which had melting temperatures above 100 degrees C, accounted for the RS contents.
Modern maize breeding and selection for large starchy kernels may have contributed to reduced contents of essential amino acids which represents a serious nutritional problem for humans and animals. A large number (1,348) of germplasm accessions belonging to 13 populations and classified into four h...
Grotewold, E; Chamberlin, M; Snook, M; Siame, B; Butler, L; Swenson, J; Maddock, S; Clair, GS; Bowen, B
Manipulation of plant natural product biosynthesis through genetic engineering is an attractive but technically challenging goal. Here, we demonstrate that different secondary metabolites can be produced in cultured maize cells by ectopic expression of the appropriate regulatory genes. Cell lines engineered to express the maize transcriptional activators C1 and R accumulate two cyanidin derivatives, which are similar to the predominant anthocyanin found in differentiated plant tissues. In contrast, cell lines that express P accumulate various 3-deoxy flavonoids. Unexpectedly, P-expressing cells in culture also accumulate phenylpropanoids and green fluorescent compounds that are targeted to different subcellular compartments. Two endogenous biosynthetic genes (c2 and a1, encoding chalcone synthase and flavanone/dihydroflavonol reductase, respectively) are independently activated by ectopic expression of either P or C1/R, and there is a dose-response relationship between the transcript level of P and the degree to which c2 or a1 is expressed. Our results support a simple model showing how the gene encoding P may act as a quantitative trait locus controlling insecticidal C-glycosyl flavone level in maize silks, and they suggest how p1 might confer a selective advantage against insect predation in maize. PMID:9596632
Oliveira, C A M; Kommers, C M; Lehmann, F K M; Fonseca, A S K; Ikuta, N; Lunge, V R
Conventional and genetically modified (GM) maize cultivars have been widely planted in Brazil to produce grains for processed food, feed, or to be consumed fresh as corn ears. This study used real-time PCR to detect GM maize in processed products and fresh commercial corn ears produced in the last two years in South Brazil. Eighteen conventional and GM maize cultivars were obtained from seed production companies and 50 commercial samples (including canned corn, corn flour, dry grains, and fresh corn ears) were purchased in small local stores and supermarkets. All samples were analyzed by real time TaqMan PCR to detect one constitutive maize gene (hmg) and three genetic regions present in GM plants (p-35S promoter, major gene cry 1A.105, and t-Nos terminator). Each commercial sample was classified as conventional or GM based on the PCR results. PCR targeting the hmg gene generated positive results from all DNA samples, which were further tested with the GM targets. These targets were not detected in the five conventional maize cultivars, but were detected in the GM seeds hosting these fragments. Analysis of processed foods identified four cultivars as conventional and six as GM, which were mostly correctly labeled. Seven (53.8%) dry grain samples were classified as conventional, while six (46.2%) were classified as GM. Three (11.1%) corn ear samples were identified as conventional, and the remaining 24 (88.9%) were GM maize. These results demonstrate the high frequency of GM maize in processed products, including fresh corn ears intended for consumption in South Brazil.
Western corn rootworm (Diabrotica virgifera virgifera; WCR) is a major coleopteran maize pest in North America and the EU, and has traditionally been managed through crop rotation and broad-spectrum soil insecticides. Genetically modified (GM) Bt-maize offers an additional means of control against W...
Perry, J. N.; Devos, Y.; Arpaia, S.; Bartsch, D.; Gathmann, A.; Hails, R. S.; Kiss, J.; Lheureux, K.; Manachini, B.; Mestdagh, S.; Neemann, G.; Ortego, F.; Schiemann, J.; Sweet, J. B.
Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality–dose relationship was integrated with a dose–distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth. PMID:20053648
Han, Xueqing; Wang, Huiyu; Chen, Hongjun; Mei, Lin; Wu, Shaoqiang; Jia, Guangle; Cheng, Tao; Zhu, Shuifang; Lin, Xiangmei
An integration event-specific fluorescent liquid bead array was developed for the simultaneous identification of 10 genetically modified (GM) maize, including Bt176, Bt11, MON810, NK603, GA21, MON88017, MON89034, MIR604, T25 and MIR162, as well as one non-GM maize. The system comprised 11 specific oligonucleotide probes labeled with an amino group and coupled to fluorescence-encoded microspheres. To enable fluorescence detection, 11 pairs of primers labeled with biotin at the 5' ends were used. The hybridization signal of biotinylated PCR product to the probe-coupled microspheres was then detected. The limit of detection of this assay was 0.1% for GM maize, which is lower than the current labeling threshold levels enforced in the EU (0.9%). The results of the positive and negative controls were consistent with their expected situation, which showed that the method was highly specific. We detected GM maize in 20 of the 1370 commercial food samples tested, which were labeled as containing maize. The overall sensitivity, specificity, rapidity and high throughput capacity of this liquid chip system suggest that it could provide a significant improvement over current methods, and potentially offer an improved platform for further research into the detection of other GM plants.
Appenzeller, Laura M; Malley, Linda; Mackenzie, Susan A; Hoban, Denise; Delaney, Bryan
DAS-Ø15Ø7-1xDAS-59122-7 (1507x59122) is a genetically modified (GM) maize hybrid that was produced by crossing of two GM maize inbreds; DAS-Ø15Ø7-1 and DAS-59122-7. This hybrid cross expresses four transgenic proteins: Cry1F and PAT (from DAS-Ø15Ø7-1) and Cry34Ab1/Cry35Ab1 and PAT (from DAS-59122-7) that confer resistance to lepidopteran and coleopteran pests and tolerance to the herbicidal active ingredient glufosinate-ammonium. The current subchronic feeding study was conducted in Sprague-Dawley rats to evaluate the potential health effects of long-term consumption of a rodent diet containing 1507x59122 maize grain compared with a diet containing maize grain from its near-isogenic control (091). Diets formulated with three unrelated non-GM commercial hybrids (3573, 35P12, 36G12) were also included for within study reference data. All diets contained 34% (w/wt) maize grain and were prepared according to the specifications of PMI((R)) Nutrition International, LLC Certified Rodent LabDiet((R)) 5002 (PMI((R)) 5002). Diets were fed ad libitum to rats for at least 92days. OECD 408 response variables from rats fed the 1507x59122 diet were compared with those from rats fed the 091 control diet. No toxicologically significant differences were observed in nutritional performance variables, clinical and neurobehavioral signs, ophthalmology, clinical pathology (hematology, clinical chemistry, coagulation, and urinalysis), organ weights, and gross and microscopic pathology between rats in the 091 and 1507x59122 treatment groups. The results from this study demonstrate that 1507x59122 maize grain is as safe and nutritious as non-GM maize grain and support the concept that crossing of two safe GM maize events results in production of a safe stacked GM event.
Zhang, Zhongbao; Zhang, Jiewei; Chen, Yajuan; Li, Ruifen; Wang, Hongzhi; Ding, Liping; Wei, Jianhua
Hexokinases (HXKs, EC 126.96.36.199) play important roles in metabolism, glucose (Glc) signaling, and phosphorylation of Glc and fructose and are ubiquitous in all organisms. Despite their physiological importance, the maize HXK (ZmHXK) genes have not been analyzed systematically. We isolated and characterized nine members of the ZmHXK gene family which were distributed on 3 of the 10 maize chromosomes. A multiple sequence alignment and motif analysis revealed that the maize ZmHXK proteins share three conserved domains. Phylogenetic analysis revealed that the ZmHXK family can be divided into four subfamilies. We identified putative cis-elements in the ZmHXK promoter sequences potentially involved in phytohormone and abiotic stress responses, sugar repression, light and circadian rhythm regulation, Ca(2+) responses, seed development and germination, and CO2-responsive transcriptional activation. To study the functions of maize HXK isoforms, we characterized the expression of the ZmHXK5 and ZmHXK6 genes, which are evolutionarily related to the OsHXK5 and OsHXK6 genes from rice. Analysis of tissue-specific expression patterns using quantitative real time-PCR showed that ZmHXK5 was highly expressed in tassels, while ZmHXK6 was expressed in both tassels and leaves. ZmHXK5 and ZmHXK6 expression levels were upregulated by phytohormones and by abiotic stress.
Jiang, Haiyang; Wu, Qingqing; Jin, Jing; Sheng, Lei; Yan, Hanwei; Cheng, Beijiu; Zhu, Suwen
Members of the ankyrin repeats (ANK) gene family encode ANK domain that are common in diverse organisms and play important roles in cell growth and development, such as cell-cell signal transduction and cell cycle regulation. Recently, genome-wide identification and evolutionary analyses of the ANK gene family have been carried out in Arabidopsis and rice. However, little is known regarding the ANK genes in the entire maize genome. In this study, we described the identification and structural characterization of 71 ANK genes in maize (ZmANK). Then, comprehensive bioinformatics analyses of ZmANK genes family were performed including phylogenetic, domain and motif analysis, chromosomal localization, intron/exon structural patterns, gene duplications and expression profiling. Domain composition analyses showed that ZmANK genes formed ten subfamilies. Five tandem duplications and 14 segmental duplications were identified in ZmANK genes. Furthermore, we took comparative analysis of the total ANK gene family in Arabidopsis, rice and maize, ZmANKs were more closely paired with OsANKs than with AtANKs. At last, expression profile analyses were performed. Forty-one members of ZmANK genes held EST sequences records. Semi-quantitative expression and microarray data analysis of these 41 ZmANK genes demonstrated that ZmANK genes exhibit a various expression pattern, suggesting that functional diversification of ZmANK genes family. The results will present significant insights to explore ANK genes expression and function in future studies in maize.
Panda, R; Ariyarathna, H; Amnuaycheewa, P; Tetteh, A; Pramod, S N; Taylor, S L; Ballmer-Weber, B K; Goodman, R E
Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for rarely allergenic plants (e.g. maize and rice). Since allergic individuals must avoid foods containing their allergen (e.g. peanut, soybean, maize, or rice), the relevance of the tests is unclear. Furthermore, no acceptance criteria are established and little is known about the natural variation in allergen concentrations in these crops. Our results demonstrate a 15-fold difference in the major maize allergen, lipid transfer protein between nine varieties, and complex variation in IgE binding to various soybean varieties. We question the value of evaluating endogenous allergens in GM plants unless the intent of the modification was production of a hypoallergenic crop.
Moon, Gi-Seong; Shin, Weon-Sun
For the quantitative analysis of genetically modified (GM) maize in processed foods, primer sets and probes based on the 35S promoter (p35S), nopaline synthase terminator (tNOS), p35S-hsp70 intron, and zSSIIb gene encoding starch synthase II for intrinsic control were designed. Polymerase chain reaction (PCR) products (80~101 bp) were specifically amplified and the primer sets targeting the smaller regions (80 or 81 bp) were more sensitive than those targeting the larger regions (94 or 101 bp). Particularly, the primer set 35F1-R1 for p35S targeting 81 bp of sequence was even more sensitive than that targeting 101 bp of sequence by a 3-log scale. The target DNA fragments were also specifically amplified from all GM labeled food samples except for one item we tested when 35F1-R1 primer set was applied. A reference plasmid pGMmaize (3 kb) including the smaller PCR products for p35S, tNOS, p35S-hsp70 intron, and the zSSIIb gene was constructed for real-time PCR (RT-PCR). The linearity of standard curves was confirmed by using diluents ranging from 2×10(1)~10(5) copies of pGMmaize and the R(2) values ranged from 0.999~1.000. In the RT-PCR, the detection limit using the novel primer/probe sets was 5 pg of genomic DNA from MON810 line indicating that the primer sets targeting the smaller regions (80 or 81 bp) could be used for highly sensitive detection of foreign DNA fragments from GM maize in processed foods.
Séralini, Gilles-Eric; Clair, Emilie; Mesnage, Robin; Gress, Steeve; Defarge, Nicolas; Malatesta, Manuela; Hennequin, Didier; de Vendômois, Joël Spiroux
The health effects of a Roundup-tolerant genetically modified maize (from 11% in the diet), cultivated with or without Roundup, and Roundup alone (from 0.1 ppb in water), were studied 2 years in rats. In females, all treated groups died 2-3 times more than controls, and more rapidly. This difference was visible in 3 male groups fed GMOs. All results were hormone and sex dependent, and the pathological profiles were comparable. Females developed large mammary tumors almost always more often than and before controls, the pituitary was the second most disabled organ; the sex hormonal balance was modified by GMO and Roundup treatments. In treated males, liver congestions and necrosis were 2.5-5.5 times higher. This pathology was confirmed by optic and transmission electron microscopy. Marked and severe kidney nephropathies were also generally 1.3-2.3 greater. Males presented 4 times more large palpable tumors than controls which occurred up to 600 days earlier. Biochemistry data confirmed very significant kidney chronic deficiencies; for all treatments and both sexes, 76% of the altered parameters were kidney related. These results can be explained by the non linear endocrine-disrupting effects of Roundup, but also by the overexpression of the transgene in the GMO and its metabolic consequences.
Cong, Bin; Maxwell, Carl; Luck, Stanley; Vespestad, Deanne; Richard, Keith; Mickelson, James; Zhong, Cathy
This study was designed to assess natural variation in composition and metabolites in 50 genetically diverse non genetically modified maize hybrids grown at six locations in North America. Results showed that levels of compositional components in maize forage were affected by environment more than genotype. Crude protein, all amino acids except lysine, manganese, and β-carotene in maize grain were affected by environment more than genotype; however, most proximates and fibers, all fatty acids, lysine, most minerals, vitamins, and secondary metabolites in maize grain were affected by genotype more than environment. A strong interaction between genotype and environment was seen for some analytes. The results could be used as reference values for future nutrient composition studies of genetically modified crops and to expand conventional compositional data sets. These results may be further used as a genetic basis for improvement of the nutritional value of maize grain by molecular breeding and biotechnology approaches.
Chopra, Surinder; Cocciolone, Suzy M; Bushman, Shaun; Sangar, Vineet; McMullen, Michael D; Peterson, Thomas
We have characterized Unstable factor for orange1 (Ufo1), a dominant, allele-specific modifier of expression of the maize pericarp color1 (p1) gene. The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments. The P1-wr allele specifies colorless kernel pericarp and red cobs, whereas Ufo1 modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. In the presence of Ufo1, P1-wr transcript levels and transcription rate are increased in kernel pericarp. The P1-wr allele contains approximately six p1 gene copies present in a hypermethylated and multicopy tandem array. In P1-wr Ufo1 plants, methylation of P1-wr DNA sequences is reduced, whereas the methylation state of other repetitive genomic sequences was not detectably affected. The phenotypes produced by the interaction of P1-wr and Ufo1 are unstable, exhibiting somatic mosaicism and variable penetrance. Moreover, the changes in P1-wr expression and methylation are not heritable: meiotic segregants that lack Ufo1 revert to the normal P1-wr expression and methylation patterns. These results demonstrate the existence of a class of modifiers of gene expression whose effects are associated with transient changes in DNA methylation of specific loci. PMID:12663550
Fantozzi, Anna; Ermolli, Monica; Marini, Massimiliano; Scotti, Domenico; Balla, Branko; Querci, Maddalena; Langrell, Stephen R H; Van den Eede, Guy
An innovative covalent microsphere immunoassay, based on the usage of fluorescent beads coupled to a specific antibody, was developed for the quantification of the endotoxin Cry1Ab present in MON810 and Bt11 genetically modified (GM) maize lines. In particular, a specific protocol was developed to assess the presence of Cry1Ab in a very broad range of GM maize concentrations, from 0.1 to 100% [weight of genetically modified organism (GMO)/weight]. Test linearity was achieved in the range of values from 0.1 to 3%, whereas fluorescence signal increased following a nonlinear model, reaching a plateau at 25%. The limits of detection and quantification were equal to 0.018 and 0.054%, respectively. The present study describes the first application of quantitative high-throughput immunoassays in GMO analysis.
Ye, Fan; Miao, Ming; Huang, Chao; Lu, Keyu; Jiang, Bo; Zhang, Tao
The octenylsuccinic groups in esterification-modified sugary maize soluble starches with a low (0.0191) or high (0.0504) degree of substitution (DS) were investigated by amyloglucosidase hydrolysis followed by a combination of chemical and physical analysis. The results showed the zeta-potential remained at approximately the same value regardless of excessive hydrolysis. The weight-average molecular weight decreased rapidly and reached 1.22 × 10(7) and 1.60 × 10(7) g/mol after 120 min for low-DS and high-DS octenylsuccinic anhydride (OSA) modified starch, respectively. The pattern of z-average radius of gyration as well as particle size change was similar to that of Mw, and z-average radius of gyration decreased much more slowly, especially for high-DS OSA starch. Compared to native starch, two characteristic absorption peaks at 1726.76 and 1571.83 cm(-1) were observed in FT-IR spectra, and the intensity of absorption peaks increased with increasing DS. The NMR results showed that OSA starch had several additional peaks at 0.8-3.0 ppm and a shoulder at 5.56 ppm for OSA substituents, which were grafted at O-2 and O-3 positions in soluble starch. The even distribution of OSA groups in the center area of soluble starch particle has been directly shown under CLSM. Most substitutions were located near branching points of soluble starch particles for a low-DS modified starch, whereas the substituted ester groups were located near branching points as well as at the nonreducing ends in OSA starch with a high DS.
Zhang, Xiaolan; Madi, Shahinez; Borsuk, Lisa; Nettleton, Dan; Elshire, Robert J; Buckner, Brent; Janick-Buckner, Diane; Beck, Jon; Timmermans, Marja; Schnable, Patrick S; Scanlon, Michael J
Microarrays enable comparative analyses of gene expression on a genomic scale, however these experiments frequently identify an abundance of differentially expressed genes such that it may be difficult to identify discrete functional networks that are hidden within large microarray datasets. Microarray analyses in which mutant organisms are compared to nonmutant siblings can be especially problematic when the gene of interest is expressed in relatively few cells. Here, we describe the use of laser microdissection microarray to perform transcriptional profiling of the maize shoot apical meristem (SAM), a ~100-microm pillar of organogenic cells that is required for leaf initiation. Microarray analyses compared differential gene expression within the SAM and incipient leaf primordium of nonmutant and narrow sheath mutant plants, which harbored mutations in the duplicate genes narrow sheath1 (ns1) and narrow sheath2 (ns2). Expressed in eight to ten cells within the SAM, ns1 and ns2 encode paralogous WUSCHEL1-like homeobox (WOX) transcription factors required for recruitment of leaf initials that give rise to a large lateral domain within maize leaves. The data illustrate the utility of laser microdissection-microarray analyses to identify a relatively small number of genes that are differentially expressed within the SAM. Moreover, these analyses reveal potentially conserved WOX gene functions and implicate specific hormonal and signaling pathways during early events in maize leaf development.
Zhang, Xiaolan; Madi, Shahinez; Borsuk, Lisa; Nettleton, Dan; Elshire, Robert J; Buckner, Brent; Janick-Buckner, Diane; Beck, Jon; Timmermans, Marja; Schnable, Patrick S; Scanlon, Michael J
Microarrays enable comparative analyses of gene expression on a genomic scale, however these experiments frequently identify an abundance of differentially expressed genes such that it may be difficult to identify discrete functional networks that are hidden within large microarray datasets. Microarray analyses in which mutant organisms are compared to nonmutant siblings can be especially problematic when the gene of interest is expressed in relatively few cells. Here, we describe the use of laser microdissection microarray to perform transcriptional profiling of the maize shoot apical meristem (SAM), a ~100-μm pillar of organogenic cells that is required for leaf initiation. Microarray analyses compared differential gene expression within the SAM and incipient leaf primordium of nonmutant and narrow sheath mutant plants, which harbored mutations in the duplicate genes narrow sheath1 (ns1) and narrow sheath2 (ns2). Expressed in eight to ten cells within the SAM, ns1 and ns2 encode paralogous WUSCHEL1-like homeobox (WOX) transcription factors required for recruitment of leaf initials that give rise to a large lateral domain within maize leaves. The data illustrate the utility of laser microdissection-microarray analyses to identify a relatively small number of genes that are differentially expressed within the SAM. Moreover, these analyses reveal potentially conserved WOX gene functions and implicate specific hormonal and signaling pathways during early events in maize leaf development. PMID:17571927
Szénási, Ágnes; Pálinkás, Zoltán; Zalai, Mihály; Schmitz, Oswald J; Balog, Adalbert
There is concern that genetically modified (GM) plants may have adverse affects on the arthropod biodiversity comprising agricultural landscapes. The present study report on a two year field experimental test of whether four different genotypic lines, some are novel with no previous field tests, of GM maize hybrids alter the structure of arthropod food webs that they harbour, relative to non-GM maize (control) that is widely used in agriculture. The different GM genotypes produced either Bt toxins, conferred glyphosate tolerance or a combination of the two traits. Quantitative food web analysis, based on short-term assessment assigning a total of 243,896 arthropod individuals collected from the treatments to their positions in food webs, revealed that complex and stable food webs persisted in each maize treatment. Moreover, food web structure remained relatively unchanged by the GM-genotype. The results suggest that at least in short-term period these particular GM maize genotypes will not have adverse effects on arthropod biota of agricultural landscapes.
Shi, Jinrui; Habben, Jeffrey E; Archibald, Rayeann L; Drummond, Bruce J; Chamberlin, Mark A; Williams, Robert W; Lafitte, H Renee; Weers, Ben P
Lack of sufficient water is a major limiting factor to crop production worldwide, and the development of drought-tolerant germplasm is needed to improve crop productivity. The phytohormone ethylene modulates plant growth and development as well as plant response to abiotic stress. Recent research has shown that modifying ethylene biosynthesis and signaling can enhance plant drought tolerance. Here, we report novel negative regulators of ethylene signal transduction in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). These regulators are encoded by the ARGOS gene family. In Arabidopsis, overexpression of maize ARGOS1 (ZmARGOS1), ZmARGOS8, Arabidopsis ARGOS homolog ORGAN SIZE RELATED1 (AtOSR1), and AtOSR2 reduced plant sensitivity to ethylene, leading to enhanced drought tolerance. RNA profiling and genetic analysis suggested that the ZmARGOS1 transgene acts between an ethylene receptor and CONSTITUTIVE TRIPLE RESPONSE1 in the ethylene signaling pathway, affecting ethylene perception or the early stages of ethylene signaling. Overexpressed ZmARGOS1 is localized to the endoplasmic reticulum and Golgi membrane, where the ethylene receptors and the ethylene signaling protein ETHYLENE-INSENSITIVE2 and REVERSION-TO-ETHYLENE SENSITIVITY1 reside. In transgenic maize plants, overexpression of ARGOS genes also reduces ethylene sensitivity. Moreover, field testing showed that UBIQUITIN1:ZmARGOS8 maize events had a greater grain yield than nontransgenic controls under both drought stress and well-watered conditions.
Healthy maize seeds have two basic endochitinases, chitA and chitB, with antifungal properties. A comparison of the isoenzyme profiles of symptomatic fungal-infested maize seeds, removed at harvest from ears that we wound inoculated in the late milk stage of maturity with one of several common ear-...
Allnutt, Theodore Richard; Dwyer, Mark; McMillan, Jillian; Henry, Christine; Langrell, Stephen
The coexistence of genetically modified (GM) and non-GM crops is an important economic and political issue in the European Union. We examined the GM content in non-GM maize crops in Spain in 2005. Both the standing crop and the harvest were tested, and the %GM DNA was quantified by real-time polymerase chain reaction. We compared the level of GM as a function of distance from known GM source fields in a 1.2 km2 landscape. The distribution of GM was compared to predictions from previous studies, and good agreement was found. Control and monitoring of adventitious GM presence in non-GM crops can only be achieved by fit-for-purpose sampling and testing schemes. We used a GM dispersal function to simulate non-GM crops in the studied zone and tested the accuracy of five different sampling schemes. Random sampling was found to be the most accurate and least susceptible to bias by GM spatial structure or gradients. Simulations showed that to achieve greater than 95% confidence in a GM labeling decision of a harvest (when treated as a single marketed lot), 34 samples would be needed when the harvest was outside 50% of the GM threshold value. The number of samples required increased rapidly as the harvest approached the GM threshold, implying that accurate labeling when the harvest is within +/-17% of the threshold may not be possible with high confidence.
Prasad, Laxmi N; Sherkat, Frank; Shah, Nagendra P
This study examined the influence of galactooligosaccharides (GOS) and modified waxy maize starch (MWMS) addition on the growth of starter cultures, and syneresis and firmness of low-fat yogurt during storage for 28 d at 4 °C. The control yogurt (CY) was prepared without any prebiotics. Incorporation of 2.0% (w/v) GOS improved the growth of L. delbrueckii ssp. bulgaricus ATCC 11842 resulting in a shorter fermentation time. There was a significant (P < 0.05) increase in proteolysis in yogurt made with GOS (GOSY) as measured by absorbance value (0.728). Addition of GOS resulted in higher (P < 0.05) concentration of lactic and acetic acids in comparison with that of MWMSY and the CY up to day 14, thereafter, the product showed a decrease in lactic acid content in all 3 batches until the end of storage. The level of syneresis was the lowest (2.14%) in MWMSY as compared with that of GOSY (2.35%) and CY (2.53%). There was no statistically significant (P > 0.05) difference in the firmness among the 3 types of yogurt.
Han, Yahui; Ding, Ting; Su, Bo; Jiang, Haiyang
Members of the chalcone synthase (CHS) family participate in the synthesis of a series of secondary metabolites in plants, fungi and bacteria. The metabolites play important roles in protecting land plants against various environmental stresses during the evolutionary process. Our research was conducted on comprehensive investigation of CHS genes in maize (Zea mays L.), including their phylogenetic relationships, gene structures, chromosomal locations and expression analysis. Fourteen CHS genes (ZmCHS01–14) were identified in the genome of maize, representing one of the largest numbers of CHS family members identified in one organism to date. The gene family was classified into four major classes (classes I–IV) based on their phylogenetic relationships. Most of them contained two exons and one intron. The 14 genes were unevenly located on six chromosomes. Two segmental duplication events were identified, which might contribute to the expansion of the maize CHS gene family to some extent. In addition, quantitative real-time PCR and microarray data analyses suggested that ZmCHS genes exhibited various expression patterns, indicating functional diversification of the ZmCHS genes. Our results will contribute to future studies of the complexity of the CHS gene family in maize and provide valuable information for the systematic analysis of the functions of the CHS gene family. PMID:26828478
Creelman, Robert A.; Griffith, Cara; Ahrens, Jeffrey E.; Taylor, J. Philip; Murphy, Lesley R.; Manjunath, Siva; Thompson, Rebecca L.; Lingard, Matthew J.; Back, Stephanie L.; Larue, Huachun; Brayton, Bonnie R.; Burek, Amanda J.; Tiwari, Shiv; Adam, Luc; Morrell, James A.; Caldo, Rico A.; Huai, Qing; Kouadio, Jean-Louis K.; Kuehn, Rosemarie; Sant, Anagha M.; Wingbermuehle, William J.; Sala, Rodrigo; Foster, Matt; Kinser, Josh D.; Mohanty, Radha; Jiang, Dongming; Ziegler, Todd E.; Huang, Mingya G.; Kuriakose, Saritha V.; Skottke, Kyle; Repetti, Peter P.; Reuber, T. Lynne; Ruff, Thomas G.; Petracek, Marie E.; Loida, Paul J.
ATHB17 (AT2G01430) is an Arabidopsis gene encoding a member of the α-subclass of the homeodomain leucine zipper class II (HD-Zip II) family of transcription factors. The ATHB17 monomer contains four domains common to all class II HD-Zip proteins: a putative repression domain adjacent to a homeodomain, leucine zipper, and carboxy terminal domain. However, it also possesses a unique N-terminus not present in other members of the family. In this study we demonstrate that the unique 73 amino acid N-terminus is involved in regulation of cellular localization of ATHB17. The ATHB17 protein is shown to function as a transcriptional repressor and an EAR-like motif is identified within the putative repression domain of ATHB17. Transformation of maize with an ATHB17 expression construct leads to the expression of ATHB17Δ113, a truncated protein lacking the first 113 amino acids which encodes a significant portion of the repression domain. Because ATHB17Δ113 lacks the repression domain, the protein cannot directly affect the transcription of its target genes. ATHB17Δ113 can homodimerize, form heterodimers with maize endogenous HD-Zip II proteins, and bind to target DNA sequences; thus, ATHB17Δ113 may interfere with HD-Zip II mediated transcriptional activity via a dominant negative mechanism. We provide evidence that maize HD-Zip II proteins function as transcriptional repressors and that ATHB17Δ113 relieves this HD-Zip II mediated transcriptional repression activity. Expression of ATHB17Δ113 in maize leads to increased ear size at silking and, therefore, may enhance sink potential. We hypothesize that this phenotype could be a result of modulation of endogenous HD-Zip II pathways in maize. PMID:24736658
Rice, Elena A; Khandelwal, Abha; Creelman, Robert A; Griffith, Cara; Ahrens, Jeffrey E; Taylor, J Philip; Murphy, Lesley R; Manjunath, Siva; Thompson, Rebecca L; Lingard, Matthew J; Back, Stephanie L; Larue, Huachun; Brayton, Bonnie R; Burek, Amanda J; Tiwari, Shiv; Adam, Luc; Morrell, James A; Caldo, Rico A; Huai, Qing; Kouadio, Jean-Louis K; Kuehn, Rosemarie; Sant, Anagha M; Wingbermuehle, William J; Sala, Rodrigo; Foster, Matt; Kinser, Josh D; Mohanty, Radha; Jiang, Dongming; Ziegler, Todd E; Huang, Mingya G; Kuriakose, Saritha V; Skottke, Kyle; Repetti, Peter P; Reuber, T Lynne; Ruff, Thomas G; Petracek, Marie E; Loida, Paul J
ATHB17 (AT2G01430) is an Arabidopsis gene encoding a member of the α-subclass of the homeodomain leucine zipper class II (HD-Zip II) family of transcription factors. The ATHB17 monomer contains four domains common to all class II HD-Zip proteins: a putative repression domain adjacent to a homeodomain, leucine zipper, and carboxy terminal domain. However, it also possesses a unique N-terminus not present in other members of the family. In this study we demonstrate that the unique 73 amino acid N-terminus is involved in regulation of cellular localization of ATHB17. The ATHB17 protein is shown to function as a transcriptional repressor and an EAR-like motif is identified within the putative repression domain of ATHB17. Transformation of maize with an ATHB17 expression construct leads to the expression of ATHB17Δ113, a truncated protein lacking the first 113 amino acids which encodes a significant portion of the repression domain. Because ATHB17Δ113 lacks the repression domain, the protein cannot directly affect the transcription of its target genes. ATHB17Δ113 can homodimerize, form heterodimers with maize endogenous HD-Zip II proteins, and bind to target DNA sequences; thus, ATHB17Δ113 may interfere with HD-Zip II mediated transcriptional activity via a dominant negative mechanism. We provide evidence that maize HD-Zip II proteins function as transcriptional repressors and that ATHB17Δ113 relieves this HD-Zip II mediated transcriptional repression activity. Expression of ATHB17Δ113 in maize leads to increased ear size at silking and, therefore, may enhance sink potential. We hypothesize that this phenotype could be a result of modulation of endogenous HD-Zip II pathways in maize.
Oliveira, G E; Von Pinho, E V R; Andrade, T; Souza, J C; Caixeta, F; Ferreira, R A D C
In this study, we analyzed heterosis, amylase enzyme gene expression, and the physiological quality of maize seeds with different genotypes and sizes, which were subjected to aging and not subjected to aging. We used seeds from 2 maize lines that differed with regard to physiological quality, the hybrid, and the reciprocal hybrid; they were classified into 2 sizes and were subjected to aging and not subjected to aging. Physiological quality was assessed by performing tests for germination, emergence, emergence speed index, and artificial aging. Expressions of the genes alpha amylase B73, alpha amylase (LOC542522), isoamylase mRNA clone 353244, and the endogenous controls ubiquitin and alcohol dehydrogenase in the seeds were studied using quantitative real-time-polymerase chain reaction. We observed heterosis for seed quality and for expression of amylase genes in the genotypes studied. We found no difference in seed quality between large and small seeds.
Che, Ping; Love, Tanzy M; Frame, Bronwyn R; Wang, Kan; Carriquiry, Alicia L; Howell, Stephen H
Gene expression patterns were profiled during somatic embryogenesis in a regeneration-proficient maize hybrid line, Hi II, in an effort to identify genes that might be used as developmental markers or targets to optimize regeneration steps for recovering maize plants from tissue culture. Gene expression profiles were generated from embryogenic calli induced to undergo embryo maturation and germination. Over 1,000 genes in the 12,060 element arrays showed significant time variation during somatic embryo development. A substantial number of genes were downregulated during embryo maturation, largely histone and ribosomal protein genes, which may result from a slowdown in cell proliferation and growth during embryo maturation. The expression of these genes dramatically recovered at germination. Other genes up-regulated during embryo maturation included genes encoding hydrolytic enzymes (nucleases, glucosidases and proteases) and a few storage genes (an alpha-zein and caleosin), which are good candidates for developmental marker genes. Germination is accompanied by the up-regulation of a number of stress response and membrane transporter genes, and, as expected, greening is associated with the up-regulation of many genes encoding photosynthetic and chloroplast components. Thus, some, but not all genes typically associated with zygotic embryogenesis are significantly up or down-regulated during somatic embryogenesis in Hi II maize line regeneration. Although many genes varied in expression throughout somatic embryo development in this study, no statistically significant gene expression changes were detected between total embryogenic callus and callus enriched for transition stage somatic embryos.
Larson, Nick B.; Marcon, Caroline; Schnable, James C.; Yeh, Cheng-Ting; Lanz, Christa; Nettleton, Dan; Piepho, Hans-Peter; Schnable, Patrick S.
Maize (Zea mays) displays an exceptional level of structural genomic diversity, which is likely unique among higher eukaryotes. In this study, we surveyed how the genetic divergence of two maize inbred lines affects the transcriptomic landscape in four different primary root tissues of their F1-hybrid progeny. An extreme instance of complementation was frequently observed: genes that were expressed in only one parent but in both reciprocal hybrids. This single-parent expression (SPE) pattern was detected for 2341 genes with up to 1287 SPE patterns per tissue. As a consequence, the number of active genes in hybrids exceeded that of their parents in each tissue by >400. SPE patterns are highly dynamic, as illustrated by their excessive degree of tissue specificity (80%). The biological significance of this type of complementation is underpinned by the observation that a disproportionally high number of SPE genes (75 to 82%) is nonsyntenic, as opposed to all expressed genes (36%). These genes likely evolved after the last whole-genome duplication and are therefore younger than the syntenic genes. In summary, SPE genes shape the remarkable gene expression plasticity between root tissues and complementation in maize hybrids, resulting in a tissue-specific increase of active genes in F1-hybrids compared with their inbred parents. PMID:25315323
Corbisier, Philippe; Bhat, Somanath; Partis, Lina; Xie, Vicki Rui Dan; Emslie, Kerry R
Quantitative analysis of genetically modified (GM) foods requires estimation of the amount of the transgenic event relative to an endogenous gene. Regulatory authorities in the European Union (EU) have defined the labelling threshold for GM food on the copy number ratio between the transgenic event and an endogenous gene. Real-time polymerase chain reaction (PCR) is currently being used for quantification of GM organisms (GMOs). Limitations in real-time PCR applications to detect very low number of DNA targets has led to new developments such as the digital PCR (dPCR) which allows accurate measurement of DNA copies without the need for a reference calibrator. In this paper, the amount of maize MON810 and hmg copies present in a DNA extract from seed powders certified for their mass content and for their copy number ratio was measured by dPCR. The ratio of these absolute copy numbers determined by dPCR was found to be identical to the ratios measured by real-time quantitative PCR (qPCR) using a plasmid DNA calibrator. These results indicate that both methods could be applied to determine the copy number ratio in MON810. The reported values were in agreement with estimations from a model elaborated to convert mass fractions into copy number fractions in MON810 varieties. This model was challenged on two MON810 varieties used for the production of MON810 certified reference materials (CRMs) which differ in the parental origin of the introduced GM trait. We conclude that dPCR has a high metrological quality and can be used for certifying GM CRMs in terms of DNA copy number ratio.
Kanobe, Milly N.; Rodermel, Steven R.; Bailey, Theodore; Scott, M. Paul
Transgenic agricultural crops with increased nutritive value present prospects for contributing to public health. However, their acceptance is poor in many countries due to the perception that genetic modification may cause unintended effects on expression of native genes in the host plant. Here, we tested effects of soybean ferritin transgene (SoyFer1, M64337) on transcript and protein levels of endogenous genes in maize. Results showed that the transgene was successfully introduced and expressed in the maize seed endosperm. mRNA abundance of seven tested iron homeostasis genes and seed storage protein genes differed significantly between seed samples positive and negative for the transgene. The PCR negative samples had higher zein and total protein content compared to the positive samples. However, PCR positive samples had significantly higher concentrations of calcium, magnesium, and iron. We have shown that the soybean ferritin transgene affected the expression of native iron homeostasis genes in the maize plant. These results underscore the importance of taking a holistic approach to the evaluation of transgenic events in target plants, comparing the transgenic plant to the untransformed controls. PMID:23785377
Kanobe, Milly N; Rodermel, Steven R; Bailey, Theodore; Scott, M Paul
Transgenic agricultural crops with increased nutritive value present prospects for contributing to public health. However, their acceptance is poor in many countries due to the perception that genetic modification may cause unintended effects on expression of native genes in the host plant. Here, we tested effects of soybean ferritin transgene (SoyFer1, M64337) on transcript and protein levels of endogenous genes in maize. Results showed that the transgene was successfully introduced and expressed in the maize seed endosperm. mRNA abundance of seven tested iron homeostasis genes and seed storage protein genes differed significantly between seed samples positive and negative for the transgene. The PCR negative samples had higher zein and total protein content compared to the positive samples. However, PCR positive samples had significantly higher concentrations of calcium, magnesium, and iron. We have shown that the soybean ferritin transgene affected the expression of native iron homeostasis genes in the maize plant. These results underscore the importance of taking a holistic approach to the evaluation of transgenic events in target plants, comparing the transgenic plant to the untransformed controls.
Vaculík, Marek; Landberg, Tommy; Greger, Maria; Luxová, Miroslava; Stoláriková, Miroslava; Lux, Alexander
Background and Aims Silicon (Si) has been shown to ameliorate the negative influence of cadmium (Cd) on plant growth and development. However, the mechanism of this phenomenon is not fully understood. Here we describe the effect of Si on growth, and uptake and subcellular distribution of Cd in maize plants in relation to the development of root tissues. Methods Young maize plants (Zea mays) were cultivated for 10 d hydroponically with 5 or 50 µm Cd and/or 5 mm Si. Growth parameters and the concentrations of Cd and Si were determined in root and shoot by atomic absorption spectrometry or inductively coupled plasma mass spectroscopy. The development of apoplasmic barriers (Casparian bands and suberin lamellae) and vascular tissues in roots were analysed, and the influence of Si on apoplasmic and symplasmic distribution of 109Cd applied at 34 nm was investigated between root and shoot. Key Results Si stimulated the growth of young maize plants exposed to Cd and influenced the development of Casparian bands and suberin lamellae as well as vascular tissues in root. Si did not affect the distribution of apoplasmic and symplasmic Cd in maize roots, but considerably decreased symplasmic and increased apoplasmic concentration of Cd in maize shoots. Conclusions Differences in Cd uptake of roots and shoots are probably related to the development of apoplasmic barriers and maturation of vascular tissues in roots. Alleviation of Cd toxicity by Si might be attributed to enhanced binding of Cd to the apoplasmic fraction in maize shoots. PMID:22455991
Ohtsu, Kazuhiro; Smith, Marianne B; Emrich, Scott J; Borsuk, Lisa A; Zhou, Ruilian; Chen, Tianle; Zhang, Xiaolan; Timmermans, Marja C P; Beck, Jon; Buckner, Brent; Janick-Buckner, Diane; Nettleton, Dan; Scanlon, Michael J; Schnable, Patrick S
All above-ground plant organs are derived from shoot apical meristems (SAMs). Global analyses of gene expression were conducted on maize (Zea mays L.) SAMs to identify genes preferentially expressed in the SAM. The SAMs were collected from 14-day-old B73 seedlings via laser capture microdissection (LCM). The RNA samples extracted from LCM-collected SAMs and from seedlings were hybridized to microarrays spotted with 37 660 maize cDNAs. Approximately 30% (10 816) of these cDNAs were prepared as part of this study from manually dissected B73 maize apices. Over 5000 expressed sequence tags (ESTs) (about 13% of the total) were differentially expressed (P<0.0001) between SAMs and seedlings. Of these, 2783 and 2248 ESTs were up- and down-regulated in the SAM, respectively. The expression in the SAM of several of the differentially expressed ESTs was validated via quantitative RT-PCR and/or in situ hybridization. The up-regulated ESTs included many regulatory genes including transcription factors, chromatin remodeling factors and components of the gene-silencing machinery, as well as about 900 genes with unknown functions. Surprisingly, transcripts that hybridized to 62 retrotransposon-related cDNAs were also substantially up-regulated in the SAM. Complementary DNAs derived from the LCM-collected SAMs were sequenced to identify additional genes that are expressed in the SAM. This generated around 550 000 ESTs (454-SAM ESTs) from two genotypes. Consistent with the microarray results, approximately 14% of the 454-SAM ESTs from B73 were retrotransposon-related. Possible roles of genes that are preferentially expressed in the SAM are discussed. PMID:17764504
Ohtsu, Kazuhiro; Smith, Marianne B; Emrich, Scott J; Borsuk, Lisa A; Zhou, Ruilian; Chen, Tianle; Zhang, Xiaolan; Timmermans, Marja C P; Beck, Jon; Buckner, Brent; Janick-Buckner, Diane; Nettleton, Dan; Scanlon, Michael J; Schnable, Patrick S
All above-ground plant organs are derived from shoot apical meristems (SAMs). Global analyses of gene expression were conducted on maize (Zea mays L.) SAMs to identify genes preferentially expressed in the SAM. The SAMs were collected from 14-day-old B73 seedlings via laser capture microdissection (LCM). The RNA samples extracted from LCM-collected SAMs and from seedlings were hybridized to microarrays spotted with 37 660 maize cDNAs. Approximately 30% (10 816) of these cDNAs were prepared as part of this study from manually dissected B73 maize apices. Over 5000 expressed sequence tags (ESTs) (about 13% of the total) were differentially expressed (P < 0.0001) between SAMs and seedlings. Of these, 2783 and 2248 ESTs were up- and down-regulated in the SAM, respectively. The expression in the SAM of several of the differentially expressed ESTs was validated via quantitative RT-PCR and/or in situ hybridization. The up-regulated ESTs included many regulatory genes including transcription factors, chromatin remodeling factors and components of the gene-silencing machinery, as well as about 900 genes with unknown functions. Surprisingly, transcripts that hybridized to 62 retrotransposon-related cDNAs were also substantially up-regulated in the SAM. Complementary DNAs derived from the LCM-collected SAMs were sequenced to identify additional genes that are expressed in the SAM. This generated around 550 000 ESTs (454-SAM ESTs) from two genotypes. Consistent with the microarray results, approximately 14% of the 454-SAM ESTs from B73 were retrotransposon-related. Possible roles of genes that are preferentially expressed in the SAM are discussed.
Hood, Elizabeth E; Bailey, Michele R; Beifuss, Katherine; Magallanes-Lundback, Maria; Horn, Michael E; Callaway, Evelyn; Drees, Carol; Delaney, Donna E; Clough, Richard; Howard, John A
Expression of industrial enzymes in transgenic plants offers an alternative system to fungal fermentation for large-scale production. Very high levels of expression are required to make the enzymes cost-effective. We tested several parameters to determine the best method for achieving high levels of expression for a fungal laccase gene. Transgenic maize plants were generated using an Agrobacterium-mediated system. The molecular parameters that induced the highest expression were the maize embryo-preferred globulin 1 promoter and targeting of the protein to the cell wall. Two independent transgenic events that yielded multiple clonal plants were characterized in detail. Independent transgenic events 01 and 03 contained two or one copies of T-DNA, respectively. Plants derived from a single transgenic event varied in expression level, and the variation in expression levels was heritable. Within the seed, expression in these plants was primarily within the embryo, and was associated with seed browning and limited germination. High oil germplasm was used to increase germination, as well as to assist in increasing expression 20-fold in five generations through breeding and selection.
Vail, Andrew W; Wang, Ping; Uefuji, Hirotaka; Samac, Deborah A; Vance, Carroll P; Wackett, Lawrence P; Sadowsky, Michael J
The widespread use of atrazine and other s-triazine herbicides to control weeds in agricultural production fields has impacted surface and groundwater in the United States and elsewhere. We previously reported the cloning, sequencing, and expression of six genes involved in the atrazine biodegradation pathway of Pseudomonas sp. strain ADP, which is initiated by atzA, encoding atrazine chlorohydrolase. Here we explored the use of enhanced expression of a modified bacterial atrazine chlorohydrolase, p-AtzA, in transgenic grasses (tall fescue, perennial ryegrass, and switchgrass) and the legume alfalfa for the biodegradation of atrazine. Enhanced expression of p-AtzA was obtained by using combinations of the badnavirus promoter, the maize alcohol dehydrogenase first intron, and the maize ubiquitin promoter. For alfalfa, we used the first intron of the 5'-untranslated region tobacco alcohol dehydrogenase gene and the cassava vein mosaic virus promoter. Resistance of plants to atrazine in agar-based and hydroponic growth assays was correlated with in vivo levels of gene expression and atrazine degradation. The in planta expression of p-atzA enabled transgenic tall fescue to transform atrazine into hydroxyatrazine and other metabolites. Results of our studies highlight the potential use of transgenic plants for bioremediating atrazine in the environment.
I describe here the organization of maize C4 chloroplast and non-C4 cytosolic pyruvate, orthophosphate dikinase (PPDK) genes and the molecular mechanisms underlying their differential expression. The maize C4 chloroplast PPDK gene (C4ppdkZm1) appears to have been created by the addition of an exon encoding the chloroplast transit peptide at a site upstream of a cytosolic PPDK gene (cyppdkZm1). A splice acceptor sequence located in the first exon of cyppdkZm1 allows the fusion of the transit peptide to the cyppdkZm1 sequences. A second cyPPDK gene (cyppdkZm2) shares extensive homology with cyppdkZm1 in the coding region and in the 5' flanking region up to the TATA box. By a novel protoplast transient expression method, I show that the light-inducible expression of C4ppdkZm1 is controlled by two expression programs mediated through separate upstream regulatory elements that are active in leaf, but inactive in root and stem. Light-mediated C4ppdkZm1 expression in maize is apparently uncoupled from leaf development and partially associated with chloroplast development. For cyppdkZm1 expression, distinct upstream elements and a specific TATA promoter element, located in the first intron of C4ppdkZm1, are required. The low expression of cyppdkZm2 can be attributed to an absence of upstream positive elements and weak activity of the TATA promoter element. PMID:1668653
Schaefer, Robert J.; Briskine, Roman; Springer, Nathan M.; Myers, Chad L.
Tools that provide improved ability to relate genotype to phenotype have the potential to accelerate breeding for desired traits and to improve our understanding of the molecular variants that underlie phenotypes. The availability of large-scale gene expression profiles in maize provides an opportunity to advance our understanding of complex traits in this agronomically important species. We built co-expression networks based on genome-wide expression data from a variety of maize accessions as well as an atlas of different tissues and developmental stages. We demonstrate that these networks reveal clusters of genes that are enriched for known biological function and contain extensive structure which has yet to be characterized. Furthermore, we found that co-expression networks derived from developmental or tissue atlases as compared to expression variation across diverse accessions capture unique functions. To provide convenient access to these networks, we developed a public, web-based Co-expression Browser (COB), which enables interactive queries of the genome-wide networks. We illustrate the utility of this system through two specific use cases: one in which gene-centric queries are used to provide functional context for previously characterized metabolic pathways, and a second where lists of genes produced by mapping studies are further resolved and validated using co-expression networks. PMID:24922320
Abreu, V M; Silva Neta, I C; Von Pinho, E V R; Naves, G M F; Guimarães, R M; Santos, H O; Von Pinho, R G
Low water availability is one of the factors that limit agricultural crop development, and hence the development of genotypes with increased water stress tolerance is a challenge in plant breeding programs. Heat-resistant proteins have been widely studied, and are reported to participate in various developmental processes and to accumulate in response to stress. This study aimed to evaluate heat-resistant protein expression under water stress conditions during the germination of maize seed inbreed lines differing in their water stress tolerance. Maize seed lines 91 and 64 were soaked in 0, -0.3, -0.6, and -0.9 MPa water potential for 0, 6, 12, 18, and 24 h. Line 91 is considered more water stress-tolerant than line 64. The analysis of heat-resistant protein expression was made by gel electrophoresis and spectrophotometry. In general, higher expression of heat-resistant proteins was observed in seeds from line 64 subjected to shorter soaking periods and lower water potentials. However, in the water stress-tolerant line 91, a higher expression was observed in seeds that were subjected to -0.3 and -0.6 MPa water potentials. In the absence of water stress, heat-resistant protein expression was reduced with increasing soaking period. Thus, there was a difference in heat-resistant protein expression among the seed lines differing in water stress tolerance. Increased heat-resistant protein expression was observed in seeds from line 91 when subjected to water stress conditions for longer soaking periods.
Cotta, Simone Raposo; Dias, Armando Cavalcante Franco; Marriel, Ivanildo Evódio; Gomes, Eliane Aparecida; van Elsas, Jan Dirk; Seldin, Lucy
The use of genetically modified (GM) plants still raises concerns about their environmental impact. The present study aimed to evaluate the possible effects of GM maize, in comparison to the parental line, on the structure and abundance of microbial communities in the rhizosphere. Moreover, the effect of soil type was addressed. For this purpose, the bacterial and fungal communities associated with the rhizosphere of GM plants were compared by culture-independent methodologies to the near-isogenic parental line. Two different soils and three stages of plant development in two different periods of the year were included. As evidenced by principal components analysis (PCA) of the PCR-DGGE profiles of evaluated community, clear differences occurred in these rhizosphere communities between soils and the periods of the year that maize was cultivated. However, there were no discernible effects of the GM lines as compared to the parental line. For all microbial communities evaluated, soil type and the period of the year that the maize was cultivated were the main factors that influenced their structures. No differences were observed in the abundances of total bacteria between the rhizospheres of GM and parental plant lines.
Batley, Jacqueline; Barker, Gary; O'Sullivan, Helen; Edwards, Keith J; Edwards, David
We have developed a computer based method to identify candidate single nucleotide polymorphisms (SNPs) and small insertions/deletions from expressed sequence tag data. Using a redundancy-based approach, valid SNPs are distinguished from erroneous sequence by their representation multiple times in an alignment of sequence reads. A second measure of validity was also calculated based on the cosegregation of the SNP pattern between multiple SNP loci in an alignment. The utility of this method was demonstrated by applying it to 102,551 maize (Zea mays) expressed sequence tag sequences. A total of 14,832 candidate polymorphisms were identified with an SNP redundancy score of two or greater. Segregation of these SNPs with haplotype indicates that candidate SNPs with high redundancy and cosegregation confidence scores are likely to represent true SNPs. This was confirmed by validation of 264 candidate SNPs from 27 loci, with a range of redundancy and cosegregation scores, in four inbred maize lines. The SNP transition/transversion ratio and insertion/deletion size frequencies correspond to those observed by direct sequencing methods of SNP discovery and suggest that the majority of predicted SNPs and insertion/deletions identified using this approach represent true genetic variation in maize.
Mano, Junichi; Furui, Satoshi; Takashima, Kaori; Koiwa, Tomohiro; Futo, Satoshi; Minegishi, Yasutaka; Akiyama, Hiroshi; Teshima, Reiko; Kurashima, Takeyo; Takabatake, Reona; Kitta, Kazumi
A GM maize event, MIR604, has been widely distributed and an analytical method to quantify its content is required to monitor the validity of food labeling. Here we report a novel real-time PCR-based quantitation method for MIR604 maize. We developed real-time PCR assays specific for MIR604 using event-specific primers designed by the trait developer, and for maize endogenous starch synthase IIb gene (SSIIb). Then, we determined the conversion factor, which is required to calculate the weight-based GM maize content from the copy number ratio of MIR604-specific DNA to the endogenous reference DNA. Finally, to validate the developed method, an interlaboratory collaborative trial according to the internationally harmonized guidelines was performed with blind samples containing MIR604 at the mixing levels of 0, 0.5, 1.0, 5.0 and 10.0%. The reproducibility (RSDr) of the developed method was evaluated to be less than 25%. The limit of quantitation of the method was estimated to be 0.5% based on the ISO 24276 guideline. These results suggested that the developed method would be suitable for practical quantitative analyses of MIR604 maize.
Gond, Surendra K; Bergen, Marshall S; Torres, Mónica S; White, James F
Endophytes are mutualistic symbionts within healthy plant tissues. In this study we isolated Bacillus spp. from seeds of several varieties of maize. Bacillus amyloliquifaciens or Bacillus subtilis were found to be present in all maize varieties examined in this study. To determine whether bacteria may produce antifungal compounds, generally lipopeptides in Bacillus spp., bacterial cultures were screened for production of lipopeptides. Lipopeptides were extracted by acid precipitation from liquid cultures of Bacillus spp. Lipopeptide extracts from Bacillus spp. isolated from Indian popcorn and yellow dent corn showed inhibitory activity against Fusarium moniliforme at 500μg per disk. Using MALDI-TOF mass spectrometry we detected the presence of antifungal iturin A, fengycin and bacillomycin in these isolates. PCR amplification also showed the presence of genes for iturin A and fengycin. B. subtilis (SG_JW.03) isolated from Indian popcorn showed strong inhibition of Arabidopsis seed mycoflora and enhanced seedling growth. We tested for the induction of defence gene expression in the host plant after treatment of plants with B. subtilis (SG_JW.03) and its lipopeptide extract using RT-qPCR. Roots of Indian popcorn seedlings treated with a suspension of B. subtilis (SG_JW.03) showed the induction of pathogenesis-related genes, including PR-1 and PR-4, which relate to plant defence against fungal pathogens. The lipopeptide extract alone did not increase the expression of these pathogenesis-related genes. Based on our study of maize endophytes, we hypothesize that, bacterial endophytes that naturally occur in many maize varieties may function to protect hosts by secreting antifungal lipopeptides that inhibit pathogens as well as inducing the up-regulation of pathogenesis-related genes of host plants (systemic acquired resistance).
Oard, James H.; Paige, David F.; Simmonds, John A.; Gradziel, Thomas M.
An airgun apparatus has been constructed for transient gene expression studies of monocots. This device utilizes compressed air from a commercial airgun to propel macroprojectile and DNA-coated tungsten particles. The β-glucuronidase (GUS) reporter gene was used to monitor transient expression in three distinct cell types of maize (Zea mays), rice (Oryza sativa), and wheat (Triticum aestivum). The highest level of GUS activity in cultured maize cells was observed when distance between stopping plate and target cells was adjusted to 4.3 centimeters. Efficiency of transformation was estimated to be 4.4 × 10−3. In a partial vacuum of 700 millimeters Hg, velocity of macroprojectile was measured at 520 meters per second with a 6% reduction in velocity at atmospheric pressure. A polyethylene film placed in the breech before firing contributed to a 12% increase in muzzle velocity. A 700 millimeters Hg level of vacuum was necessary for maximum number of transfornants. GUS expression was also detected in wheat leaf base tissue of microdissected shoot apices. High levels of transient gene expression were also observed in hard, compact embryogenic callus of rice. These results show that the airgun apparatus is a convenient, safe, and low-cost device for rapid transient gene expression studies in cereals. Images Figure 7 Figure 8 Figure 9 PMID:16667278
Shi, Liyu; Weng, Jianfeng; Liu, Changlin; Song, Xinyuan; Miao, Hongqin; Hao, Zhuanfang; Xie, Chuanxiao; Li, Mingshun; Zhang, Degui; Bai, Li; Pan, Guangtang; Li, Xinhai; Zhang, Shihuang
Maize rough dwarf disease (MRDD, a viral disease) results in significant grain yield losses, while genetic basis of which is largely unknown. Based on comparative genomics, eukaryotic translation initiation factor 4E (eIF4E) was considered as a candidate gene for MRDD resistance, validation of which will help to understand the possible genetic mechanism of this disease. ZmeIF4E (orthologs of eIF4E gene in maize) encodes a protein of 218 amino acids, harboring five exons and no variation in the cDNA sequence is identified between the resistant inbred line, X178 and susceptible one, Ye478. ZmeIF4E expression was different in the two lines plants treated with three plant hormones, ethylene, salicylic acid, and jasmonates at V3 developmental stage, suggesting that ZmeIF4E is more likely to be involved in the regulation of defense gene expression and induction of local and systemic resistance. Moreover, four cis-acting elements related to plant defense responses, including DOFCOREZM, EECCRCAH1, GT1GAMSCAM4, and GT1CONSENSUS were detected in ZmeIF4E promoter for harboring sequence variation in the two lines. Association analysis with 163 inbred lines revealed that one SNP in EECCRCAH1 is significantly associated with CSI of MRDD in two environments, which explained 3.33 and 9.04 % of phenotypic variation, respectively. Meanwhile, one SNP in GT-1 motif was found to affect MRDD resistance only in one of the two environments, which explained 5.17 % of phenotypic variation. Collectively, regulatory motifs respectively harboring the two significant SNPs in ZmeIF4E promoter could be involved in the defense process of maize after viral infection. These results contribute to understand maize defense mechanisms against maize rough dwarf virus.
Zhang, Zhongbao; Li, Xianglong; Yu, Rong; Han, Meng; Wu, Zhongyi
TIFY, previously known as ZIM, comprises a plant-specific family annotated as transcription factors that might play important roles in stress response. Despite TIFY proteins have been reported in Arabidopsis and rice, a comprehensive and systematic survey of ZmTIFY genes has not yet been conducted. To investigate the functions of ZmTIFY genes in this family, we isolated and characterized 30 ZmTIFY (1 TIFY, 3 ZML, and 26 JAZ) genes in an analysis of the maize (Zea mays L.) genome in this study. The 30 ZmTIFY genes were distributed over eight chromosomes. Multiple alignment and motif display results indicated that all ZmTIFY proteins share two conserved TIFY and Jas domains. Phylogenetic analysis revealed that the ZmTIFY family could be divided into two groups. Putative cis-elements, involved in abiotic stress response, phytohormones, pollen grain, and seed development, were detected in the promoters of maize TIFY genes. Microarray data showed that the ZmTIFY genes had tissue-specific expression patterns in various maize developmental stages and in response to biotic and abiotic stresses. The results indicated that ZmTIFY4, 5, 8, 26, and 28 were induced, while ZmTIFY16, 13, 24, 27, 18, and 30 were suppressed, by drought stress in the maize inbred lines Han21 and Ye478. ZmTIFY1, 19, and 28 were upregulated after infection by three pathogens, whereas ZmTIFY4, 13, 21, 23, 24, and 26 were suppressed. These results indicate that the ZmTIFY family may have vital roles in response to abiotic and biotic stresses. The data presented in this work provide vital clues for further investigating the functions of the genes in the ZmTIFY family.
Guillaumie, Sabine; San-Clemente, Hélène; Deswarte, Caroline; Martinez, Yves; Lapierre, Catherine; Murigneux, Alain; Barrière, Yves; Pichon, Magalie; Goffner, Deborah
An extensive search for maize (Zea mays) genes involved in cell wall biosynthesis and assembly has been performed and 735 sequences have been centralized in a database, MAIZEWALL (http://www.polebio.scsv.ups-tlse.fr/MAIZEWALL). MAIZEWALL contains a bioinformatic analysis for each entry and gene expression data that are accessible via a user-friendly interface. A maize cell wall macroarray composed of a gene-specific tag for each entry was also constructed to monitor global cell wall-related gene expression in different organs and during internode development. By using this macroarray, we identified sets of genes that exhibit organ and internode-stage preferential expression profiles. These data provide a comprehensive fingerprint of cell wall-related gene expression throughout the maize plant. Moreover, an in-depth examination of genes involved in lignin biosynthesis coupled to biochemical and cytological data from different organs and stages of internode development has also been undertaken. These results allow us to trace spatially and developmentally regulated, putative preferential routes of monolignol biosynthesis involving specific gene family members and suggest that, although all of the gene families of the currently accepted monolignol biosynthetic pathway are conserved in maize, there are subtle differences in family size and a high degree of complexity in spatial expression patterns. These differences are in keeping with the diversity of lignified cell types throughout the maize plant. PMID:17098859
Murry, L E; Elliott, L G; Capitant, S A; West, J A; Hanson, K K; Scarafia, L; Johnston, S; DeLuca-Flaherty, C; Nichols, S; Cunanan, D
The maize dwarf mosaic virus strain B (MDMV-B) coat protein (cp) gene was cloned into a monocot expression cassette and introduced into sweet corn cell suspension cultures via particle bombardment or electroporation. Transformed cells were selected on culture media containing 300 mg/l kanamycin, and plants were regenerated. Cells from all transformed lines expressed the cp gene; and one transgenic line synthesized approximately 100-200 micrograms MDMV-cp per gram fresh weight. Plants regenerated from this line were challenged with a virus inoculum concentration adjusted to produce symptoms in nontransgenic controls at six days post inoculation. In growth chamber studies, the presence of the MDMV-cp provided resistance to inoculations with MDMV-A or MDMV-B and to mixed inoculations of MDMV and maize chlorotic mottle virus.
Song, Jian; Guo, Baojian; Song, Fangwei; Peng, Huiru; Yao, Yingyin; Zhang, Yirong; Sun, Qixin; Ni, Zhongfu
Gibberellin (GA) is an essential phytohormone that controls many aspects of plant development. To enhance our understanding of GA metabolism in maize, we intensively screened and identified 27 candidate genes encoding the seven GA metabolic enzymes including ent-copalyl diphosphate synthase (CPS), ent-kaurene synthase (KS), ent-kaurene oxidase (KO), ent-kaurenoic acid oxidase (KAO), GA 20-oxidase (GA20ox), GA 3-oxidase (GA3ox), and GA 2-oxidase (GA2ox), using all available public maize databases. The results indicate that maize genome contains three CPS, four KS, two KO and one KAO genes, and most of them are arranged separately on the maize genome, which differs from that in rice. In addition, the enzymes catalyzing the later steps (ZmGA20ox, ZmGA3ox and ZmGA2ox) are also encoded by gene families in maize, but GA3ox enzyme is likely to be encoded by single gene. Expression profiling analysis exhibited that transcripts of 15 GA metabolic genes could be detected during maize seed germination, which provides further evidence for the notion that increased synthesis of active GA in the embryo is required for triggering germination events. Moreover, a variety of temporal genes expression patterns of GA metabolic genes were detected, which revealed the complexity of underlying mechanism for GA regulated seed germination.
Zhang, Zhongbao; Li, Xianglong; Zhang, Chun; Zou, Huawen; Wu, Zhongyi
NUCLEAR FACTOR-Y (NF-Y) has been shown to play an important role in growth, development, and response to environmental stress. A NF-Y complex, which consists of three subunits, NF-YA, NF-YB, and, NF-YC, binds to CCAAT sequences in a promoter to control the expression of target genes. Although NF-Y proteins have been reported in Arabidopsis and rice, a comprehensive and systematic analysis of ZmNF-Y genes has not yet been performed. To examine the functions of ZmNF-Y genes in this family, we isolated and characterized 50 ZmNF-Y (14 ZmNF-YA, 18 ZmNF-YB, and 18 ZmNF-YC) genes in an analysis of the maize genome. The 50 ZmNF-Y genes were distributed on all 10 maize chromosomes, and 12 paralogs were identified. Multiple alignments showed that maize ZmNF-Y family proteins had conserved regions and relatively variable N-terminal or C-terminal domains. The comparative syntenic map illustrated 40 paralogous NF-Y gene pairs among the 10 maize chromosomes. Microarray data showed that the ZmNF-Y genes had tissue-specific expression patterns in various maize developmental stages and in response to biotic and abiotic stresses. The results suggested that ZmNF-YB2, 4, 8, 10, 13, and 16 and ZmNF-YC6, 8, and 15 were induced, while ZmNF-YA1, 3, 4, 6, 7, 10, 12, and 13, ZmNF-YB15, and ZmNF-YC3 and 9 were suppressed by drought stress. ZmNF-YA3, ZmNF-YA8 and ZmNF-YA12 were upregulated after infection by the three pathogens, while ZmNF-YA1 and ZmNF-YB2 were suppressed. These results indicate that the ZmNF-Ys may have significant roles in the response to abiotic and biotic stresses.
Chaumont, François; Barrieu, François; Herman, Eliot M.; Chrispeels, Maarten J.
We studied aquaporins in maize (Zea mays), an important crop in which numerous studies on plant water relations have been carried out. A maize cDNA, ZmTIP1, was isolated by reverse transcription-coupled PCR using conserved motifs from plant aquaporins. The derived amino acid sequence of ZmTIP1 shows 76% sequence identity with the tonoplast aquaporin γ-TIP (tonoplast intrinsic protein) from Arabidopsis. Expression of ZmTIP1 in Xenopus laevis oocytes showed that it increased the osmotic water permeability of oocytes 5-fold; this water transport was inhibited by mercuric chloride. A cross-reacting antiserum made against bean α-TIP was used for immunocytochemical localization of ZmTIP1. These results indicate that this and/or other aquaporins is abundantly present in the small vacuoles of meristematic cells. Northern analysis demonstrated that ZmTIP1 is expressed in all plant organs. In situ hybridization showed a high ZmTIP1 expression in meristems and zones of cell enlargement: tips of primary and lateral roots, leaf primordia, and male and female inflorescence meristems. The high ZmTIP1 expression in meristems and expanding cells suggests that ZmTIP1 is needed (a) for vacuole biogenesis and (b) to support the rapid influx of water into vacuoles during cell expansion. PMID:9701570
Bt-maize (MON810) and non-GM soybean meal in diets for Atlantic salmon (Salmo salar L.) juveniles--impact on survival, growth performance, development, digestive function, and transcriptional expression of intestinal immune and stress responses.
Gu, Jinni; Bakke, Anne Marie; Valen, Elin C; Lein, Ingrid; Krogdahl, Åshild
Responses in Atlantic salmon (Salmo salar L.) juveniles (fry) fed diets containing genetically modified maize (Bt-maize, MON810) expressing Cry1Ab protein from first-feeding were investigated during a 99-day feeding trial. Four experimental diets were made; each diet contained ∼20% maize, either Bt-maize or its near-isogenic maternal line (non-GM maize). One pair was fishmeal-based while the other pair included standard (extracted) soybean meal (SBM; 16.7% inclusion level), with the intention of investigating responses to the maize varieties in healthy fish as well as in immunologically challenged fish with SBM-induced distal intestinal inflammation, respectively. Three replicate tanks of fry (0.17±0.01 g; initial mean weight ± SEM) were fed one of the four diets and samples were taken on days 15, 36, 48 and 99. Survival, growth performance, whole body composition, digestive function, morphology of intestine, liver and skeleton, and mRNA expression of some immune and stress response parameters in the distal intestine were evaluated. After 99 days of feeding, survival was enhanced and the intended SBM-induced inflammatory response in the distal intestine of the two groups of SBM-fed fish was absent, indicating that the juvenile salmon were tolerant to SBM. Mortality, growth performance and body composition were similar in fish fed the two maize varieties. The Bt-maize fed fish, however, displayed minor but significantly decreased digestive enzyme activities of leucine aminopeptidase and maltase, as well as decreased concentration of gut bile salts, but significantly increased amylase activity at some sampling points. Histomorphological, radiographic and mRNA expression evaluations did not reveal any biologically relevant effects of Bt-maize in the gastrointestinal tract, liver or skeleton. The results suggest that the Cry1Ab protein or other compositional differences in GM Bt-maize may cause minor alterations in intestinal responses in juvenile salmon, but
Bt-maize (MON810) and Non-GM Soybean Meal in Diets for Atlantic Salmon (Salmo salar L.) Juveniles – Impact on Survival, Growth Performance, Development, Digestive Function, and Transcriptional Expression of Intestinal Immune and Stress Responses
Gu, Jinni; Bakke, Anne Marie; Valen, Elin C.; Lein, Ingrid; Krogdahl, Åshild
Responses in Atlantic salmon (Salmo salar L.) juveniles (fry) fed diets containing genetically modified maize (Bt-maize, MON810) expressing Cry1Ab protein from first-feeding were investigated during a 99-day feeding trial. Four experimental diets were made; each diet contained ∼20% maize, either Bt-maize or its near-isogenic maternal line (non-GM maize). One pair was fishmeal-based while the other pair included standard (extracted) soybean meal (SBM; 16.7% inclusion level), with the intention of investigating responses to the maize varieties in healthy fish as well as in immunologically challenged fish with SBM-induced distal intestinal inflammation, respectively. Three replicate tanks of fry (0.17±0.01 g; initial mean weight ± SEM) were fed one of the four diets and samples were taken on days 15, 36, 48 and 99. Survival, growth performance, whole body composition, digestive function, morphology of intestine, liver and skeleton, and mRNA expression of some immune and stress response parameters in the distal intestine were evaluated. After 99 days of feeding, survival was enhanced and the intended SBM-induced inflammatory response in the distal intestine of the two groups of SBM-fed fish was absent, indicating that the juvenile salmon were tolerant to SBM. Mortality, growth performance and body composition were similar in fish fed the two maize varieties. The Bt-maize fed fish, however, displayed minor but significantly decreased digestive enzyme activities of leucine aminopeptidase and maltase, as well as decreased concentration of gut bile salts, but significantly increased amylase activity at some sampling points. Histomorphological, radiographic and mRNA expression evaluations did not reveal any biologically relevant effects of Bt-maize in the gastrointestinal tract, liver or skeleton. The results suggest that the Cry1Ab protein or other compositional differences in GM Bt-maize may cause minor alterations in intestinal responses in juvenile salmon, but
Bovy, Arnaud; de Vos, Ric; Kemper, Mark; Schijlen, Elio; Almenar Pertejo, Maria; Muir, Shelagh; Collins, Geoff; Robinson, Sue; Verhoeyen, Martine; Hughes, Steve; Santos-Buelga, Celestino; van Tunen, Arjen
Flavonoids are a group of polyphenolic plant secondary metabolites important for plant biology and human nutrition. In particular flavonols are potent antioxidants, and their dietary intake is correlated with a reduced risk of cardiovascular diseases. Tomato fruit contain only in their peel small amounts of flavonoids, mainly naringenin chalcone and the flavonol rutin, a quercetin glycoside. To increase flavonoid levels in tomato, we expressed the maize transcription factor genes LC and C1 in the fruit of genetically modified tomato plants. Expression of both genes was required and sufficient to upregulate the flavonoid pathway in tomato fruit flesh, a tissue that normally does not produce any flavonoids. These fruit accumulated high levels of the flavonol kaempferol and, to a lesser extent, the flavanone naringenin in their flesh. All flavonoids detected were present as glycosides. Anthocyanins, previously reported to accumulate upon LC expression in several plant species, were present in LC/C1 tomato leaves but could not be detected in ripe LC/C1 fruit. RNA expression analysis of ripening fruit revealed that, with the exception of chalcone isomerase, all of the structural genes required for the production of kaempferol-type flavonols and pelargonidin-type anthocyanins were induced strongly by the LC/C1 transcription factors. Expression of the genes encoding flavanone-3'-hydroxylase and flavanone-3'5'-hydroxylase, which are required for the modification of B-ring hydroxylation patterns, was not affected by LC/C1. Comparison of flavonoid profiles and gene expression data between tomato leaves and fruit indicates that the absence of anthocyanins in LC/C1 fruit is attributable primarily to an insufficient expression of the gene encoding flavanone-3'5'-hydroxylase, in combination with a strong preference of the tomato dihydroflavonol reductase enzyme to use the flavanone-3'5'-hydroxylase reaction product dihydromyricetin as a substrate.
Guo, Mei; Rupe, Mary A; Yang, Xiaofeng; Crasta, Oswald; Zinselmeier, Christopher; Smith, Oscar S; Bowen, Ben
Heterosis, or hybrid vigor, has been widely exploited in plant breeding for many decades, but the molecular mechanisms underlying the phenomenon remain unknown. In this study, we applied genome-wide transcript profiling to gain a global picture of the ways in which a large proportion of genes are expressed in the immature ear tissues of a series of 16 maize hybrids that vary in their degree of heterosis. Key observations include: (1) the proportion of allelic additively expressed genes is positively associated with hybrid yield and heterosis; (2) the proportion of genes that exhibit a bias towards the expression level of the paternal parent is negatively correlated with hybrid yield and heterosis; and (3) there is no correlation between the over- or under-expression of specific genes in maize hybrids with either yield or heterosis. The relationship of the expression patterns with hybrid performance is substantiated by analysis of a genetically improved modern hybrid (Pioneer hybrid 3394) versus a less improved older hybrid (Pioneer hybrid 3306) grown at different levels of plant density stress. The proportion of allelic additively expressed genes is positively associated with the modern high yielding hybrid, heterosis and high yielding environments, whereas the converse is true for the paternally biased gene expression. The dynamic changes of gene expression in hybrids responding to genotype and environment may result from differential regulation of the two parental alleles. Our findings suggest that differential allele regulation may play an important role in hybrid yield or heterosis, and provide a new insight to the molecular understanding of the underlying mechanisms of heterosis.
Jia, Meng-Ao; Li, Yongqiang; Lei, Lei; Di, Dianping; Miao, Hongqin; Fan, Zaifeng
Maize rough dwarf disease caused by Rice black-streaked dwarf virus (RBSDV) is a major viral disease in China. It has been suggested that the viral infection of plants might cause distinct disease symptoms through the inhibition or activation of host gene transcription. We scanned the gene expression profile of RBSDV-infected maize through oligomer-based microarrays to reveal possible expression changes associated with symptom development. Our results demonstrate that various resistance-related maize genes and cell wall- and development-related genes, such as those for cellulose synthesis, are among the genes whose expression is dramatically altered. These results could aid in research into new strategies to protect cereal crops against viruses, and reveal the molecular mechanisms of development of specific symptoms in rough dwarf-related diseases.
Zhang, Zhongbao; Li, Huiyong; Zhang, Dengfeng; Liu, Yinghui; Fu, Jing; Shi, Yunsu; Song, Yanchun; Wang, Tianyu; Li, Yu
MADS-box genes encode a family of transcription factors, which control diverse developmental processes in flowering plants, with organs ranging from roots, flowers and fruits. In this study, six maize cDNAs encoding MADS-box proteins were isolated. BLASTX searches and phylogenetic analysis indicated that the six MADS-box genes belonging to the AGL2-like clade. qRT-PCR analysis revealed that these genes had differential expression patterns in different organs in maize. The results of yeast one-hybrid system indicated that the protein ZMM3-1, ZMM3-2, ZMM6, ZMM7-L, ZMM8-L and ZMM14-L had transcriptional activation activity. Subcellular localization of ZMM7-L demonstrated that the fluorescence of ZMM7-L-GFP was mainly detected in the nuclei of onion epidermal cells. qRT-PCR analysis for expression pattern of ZMM7-L showed that the gene was up-regulated by abiotic stresses and down-regulated by exogenous ABA. The germination rates of over-expression transgenic lines were lower than that of the wild type on medium with 150 mM NaCl, 350 mM mannitol. These results indicated that ZMM7-L might be a negative transcription factor responsive to abiotic stresses.
Song, Rentao; Messing, Joachim
Genomic regions of nearly every species diverged into different haplotypes, mostly based on point mutations, small deletions, and insertions that do not affect the collinearity of genes within a species. However, the same genomic interval containing the z1C gene cluster of two inbred lines of Zea mays significantly lost their gene collinearity and also differed in the regulation of each remaining gene set. Furthermore, when inbreds were reciprocally crossed, hybrids exhibited an unexpected shift of expression patterns so that “overdominance” instead of “dominance complementation” of allelic and nonallelic gene expression occurred. The same interval also differed in length (360 vs. 263 kb). Segmental rearrangements led to sequence changes, which were further enhanced by the insertion of different transposable elements. Changes in gene order affected not only z1C genes but also three unrelated genes. However, the orthologous interval between two subspecies of rice (not rice cultivars) was conserved in length and gene order, whereas changes between two maize inbreds were as drastic as changes between maize and sorghum. Given that chromosomes could conceivably consist of intervals of haplotypes that are highly diverged, one could envision endless breeding opportunities because of their linear arrangement along a chromosome and their expression potential in hybrid combinations (“binary” systems). The implication of such a hypothesis for heterosis is discussed. PMID:12853580
Tnani, Hedia; García-Muniz, Nora; Vicient, Carlos M; López-Ribera, Ignacio
The scutellum is a shield-shaped structure surrounding the embryo axis in grass species. The scutellar epithelium (Sep) is a monolayer of cells in contact with the endosperm. The Sep plays an important role during seed germination in the secretion of gibberellins and hydrolytic enzymes and in the transport of the hydrolized products to the growing embryo. We identified 30 genes predominantly expressed after imbibition in the Sep as compared to other parts of the scutellum. A high proportion of these genes is involved in metabolic processes. Some other identified genes are involved in the synthesis or modification of cell walls, which may be reflected in the changes of cell shape and cell wall composition that can be observed during imbibition. One of the genes encodes a proteinase that belongs to a proteinase family typical of carnivorous plants. Almost nothing is known about their role in other plants or organs, but the scutellar presence may point to a "digestive" function during germination. Genes involved in the production of energy and the transport of peptides were also identified.
A laboratory colony of western corn rootworm, Diabrotica virgifera virgifera LeConte, was selected for resistance to transgenic maize expressing the eCry3.1ab protein. The selected colony was developed by rearing larvae on non-elite, non-commercial Bt maize expressing the eCry3.1Ab protein. After ...
Sui, Zhongquan; BeMiller, James N
Starches from 5 inbred lines of normal maize with different relative average degrees of channelization (RADC) that could be divided into two groups (2 with RADC values of 1.49-1.52 and 3 with RADC values of 0.10-0.17) were reacted with 4 highly reactive reagents. No consistent correlations between RADC and the effects of derivatization with the 4 reagents on physical properties, either without or after surface protein removal, were found. Reaction with propylene oxide, a slowly reacting reagent whose reaction should be independent of RADC, resulted in an inverse relationship between several physical properties and RADC. The results indicate that there are inherent granular and molecular differences in the maize starches that control reactivity that are more influential than RADC (at least with the degrees of modification used), that the differences carry through chemical derivatization, and that different reagents react differently with different starches.
Waminal, Nomar Espinosa; Ryu, Ki Hyun; Choi, Sun-Hee; Kim, Hyun Hee
Monitoring of genetically modified (GM) crops has been emphasized to prevent their potential effects on the environment and human health. Monitoring of the inadvertent dispersal of transgenic maize in several fields and transport routes in Korea was carried out by qualitative multiplex PCR, and molecular analyses were conducted to identify the events of the collected GM maize. Cytogenetic investigations through fluorescence in situ hybridization (FISH) of the GM maize were performed to check for possible changes in the 45S rDNA cluster because this cluster was reported to be sensitive to replication and transcription stress. Three GM maize kernels were collected from a transport route near Incheon port, Korea, and each was found to contain NK603, stacked MON863 x NK603, and stacked NK603 x MON810 inserts, respectively. Cytogenetic analysis of the GM maize containing the stacked NK603 x MON810 insert revealed two normal compact 5S rDNA signals, but the 45S rDNA showed a fragile phenotype, demonstrating a "beads-on-a-string" fragmentation pattern, which seems to be a consequence of genetic modification. Implications of the 45S rDNA cluster fragility in GM maize are also discussed.
Mano, Junichi; Masubuchi, Tomoko; Hatano, Shuko; Futo, Satoshi; Koiwa, Tomohiro; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Akiyama, Hiroshi; Teshima, Reiko; Kurashima, Takeyo; Takabatake, Reona; Kitta, Kazumi
In this article, we report a novel real-time PCR-based analytical method for quantitation of the GM maize event LY038. We designed LY038-specific and maize endogenous reference DNA-specific PCR amplifications. After confirming the specificity and linearity of the LY038-specific PCR amplification, we determined the conversion factor required to calculate the weight-based content of GM organism (GMO) in a multilaboratory evaluation. Finally, in order to validate the developed method, an interlaboratory collaborative trial according to the internationally harmonized guidelines was performed with blind DNA samples containing LY038 at the mixing levels of 0, 0.5, 1.0, 5.0 and 10.0%. The precision of the method was evaluated as the RSD of reproducibility (RSDR), and the values obtained were all less than 25%. The limit of quantitation of the method was judged to be 0.5% based on the definition of ISO 24276 guideline. The results from the collaborative trial suggested that the developed quantitative method would be suitable for practical testing of LY038 maize.
Seeve, Candace M; Cho, In-Jeong; Hearne, Leonard B; Srivastava, Gyan Prakash; Joshi, Trupti; Smith, Dante O; Sharp, Robert E; Oliver, Melvin J
Plants tolerate water deficits by regulating gene networks controlling cellular and physiological traits to modify growth and development. Transcription factor (TF)-directed regulation of transcription within these gene networks is key to eliciting appropriate responses. In this study, reverse transcription quantitative PCR (RT-qPCR) was used to examine the abundance of 618 transcripts from 536 TF genes in individual root and shoot tissues of maize seedlings grown in vermiculite under well-watered (water potential of -0.02 MPa) and water-deficit conditions (water potentials of -0.3 and -1.6 MPa). A linear mixed model identified 433 TF transcripts representing 392 genes that differed significantly in abundance in at least one treatment, including TFs that intersect growth and development and environmental stress responses. TFs were extensively differentially regulated across stressed maize seedling tissues. Hierarchical clustering revealed TFs with stress-induced increased abundance in primary root tips that likely regulate root growth responses to water deficits, possibly as part of abscisic acid and/or auxin-dependent signaling pathways. Ten of these TFs were selected for validation in nodal root tips of drought-stressed field-grown plants (late V1 to early V2 stage). Changes in abundance of these TF transcripts under a field drought were similar to those observed in the seedling system.
Li, Bei; Liu, Hua; Zhang, Yue; Kang, Tao; Zhang, Li; Tong, Jianhua; Xiao, Langtao; Zhang, Hongxia
Grain size, number and starch content are important determinants of grain yield and quality. One of the most important biological processes that determine these components is the carbon partitioning during the early grain filling, which requires the function of cell wall invertase. Here, we showed the constitutive expression of cell wall invertase-encoding gene from Arabidopsis, rice (Oryza sativa) or maize (Zea mays), driven by the cauliflower mosaic virus (CaMV) 35S promoter, all increased cell wall invertase activities in different tissues and organs, including leaves and developing seeds, and substantially improved grain yield up to 145.3% in transgenic maize plants as compared to the wild-type plants, an effect that was reproduced in our 2-year field trials at different locations. The dramatically increased grain yield is due to the enlarged ears with both enhanced grain size and grain number. Constitutive expression of the invertase-encoding gene also increased total starch content up to 20% in the transgenic kernels. Our results suggest that cell wall invertase gene can be genetically engineered to improve both grain yield and grain quality in crop plants.
Wang, Guifeng; Zhong, Mingyu; Wang, Jiajia; Zhang, Jushan; Tang, Yuanping; Wang, Gang; Song, Rentao
The actin-based myosin system is essential for the organization and dynamics of the endomembrane system and transport network in plant cells. Plants harbour two unique myosin groups, class VIII and class XI, and the latter is structurally and functionally analogous to the animal and fungal class V myosin. Little is known about myosins in grass, even though grass includes several agronomically important cereal crops. Here, we identified 14 myosin genes from the genome of maize (Zea mays). The relatively larger sizes of maize myosin genes are due to their much longer introns, which are abundant in transposable elements. Phylogenetic analysis indicated that maize myosin genes could be classified into class VIII and class XI, with three and 11 members, respectively. Apart from subgroup XI-F, the remaining subgroups were duplicated at least in one analysed lineage, and the duplication events occurred more extensively in Arabidopsis than in maize. Only two pairs of maize myosins were generated from segmental duplication. Expression analysis revealed that most maize myosin genes were expressed universally, whereas a few members (XI-1, -6, and -11) showed an anther-specific pattern, and many underwent extensive alternative splicing. We also found a short transcript at the O1 locus, which conceptually encoded a headless myosin that most likely functions at the transcriptional level rather than via a dominant-negative mechanism at the translational level. Together, these data provide significant insights into the evolutionary and functional characterization of maize myosin genes that could transfer to the identification and application of homologous myosins of other grasses.
Testing potential effects of maize expressing the Bacillus thuringiensis Cry1Ab endotoxin (Bt maize) on mycorrhizal fungal communities via DNA- and RNA-based pyrosequencing and molecular fingerprinting.
Verbruggen, Erik; Kuramae, Eiko E; Hillekens, Remy; de Hollander, Mattias; Kiers, E Toby; Röling, Wilfred F M; Kowalchuk, George A; van der Heijden, Marcel G A
The cultivation of genetically modified (GM) crops has increased significantly over the last decades. However, concerns have been raised that some GM traits may negatively affect beneficial soil biota, such as arbuscular mycorrhizal fungi (AMF), potentially leading to alterations in soil functioning. Here, we test two maize varieties expressing the Bacillus thuringiensis Cry1Ab endotoxin (Bt maize) for their effects on soil AM fungal communities. We target both fungal DNA and RNA, which is new for AM fungi, and we use two strategies as an inclusive and robust way of detecting community differences: (i) 454 pyrosequencing using general fungal rRNA gene-directed primers and (ii) terminal restriction fragment length polymorphism (T-RFLP) profiling using AM fungus-specific markers. Potential GM-induced effects were compared to the normal natural variation of AM fungal communities across 15 different agricultural fields. AM fungi were found to be abundant in the experiment, accounting for 8% and 21% of total recovered DNA- and RNA-derived fungal sequences, respectively, after 104 days of plant growth. RNA- and DNA-based sequence analyses yielded most of the same AM fungal lineages. Our research yielded three major conclusions. First, no consistent differences were detected between AM fungal communities associated with GM plants and non-GM plants. Second, temporal variation in AMF community composition (between two measured time points) was bigger than GM trait-induced variation. Third, natural variation of AMF communities across 15 agricultural fields in The Netherlands, as well as within-field temporal variation, was much higher than GM-induced variation. In conclusion, we found no indication that Bt maize cultivation poses a risk for AMF.
Hase, Toshiharu; Kimata, Yoko; Yonekura, Keiko; Matsumura, Tomohiko; Sakakibara, Hitoshi
In maize (Zea mays L.), four ferredoxin (Fd) isoproteins, Fd I to Fd IV, are differentially distributed in photosynthetic and nonphotosynthetic organs of young seedlings (Y Kimata, T Hase  Plant Physiol 89: 1193-1197). To understand structural characteristics of the Fd isoproteins and molecular mechanism of the differential expression of their genes, we have cloned and characterized three different maize Fd cDNAs. DNA sequence analyses showed that two of the cDNAs encoded the entire precursor polypeptides of Fd I and Fd III, which were composed of 150 and 152 amino acid residues, respectively, and the other encoded a 135 amino acid precursor polypeptide of Fd not yet identified. High degrees of homologies were found in the deduced amino acid sequences of mature regions of these Fd isoproteins, but the transit peptide of Fd III differed considerably from those of other Fd isoproteins. Fd I and the unidentified Fd were encoded mainly with codons ending in C or G, but such strong codon bias was not seen in Fd III. Gene specific probes for each cDNA were used to probe Northern blots of RNA isolated from leaves, mesocotyls, and roots of maize seedlings. The gene transcripts for Fd I and the unidentified Fd were restricted to leaves and their levels increased markedly upon illumination of etiolated seedlings, whereas that for Fd III was detected in all organs and its accumulation was not light dependent. This organ specific accumulation of Fd mRNAs corresponds exactly to the distribution pattern of Fd isoproteins. ImagesFigure 1Figure 5Figure 6Figure 7Figure 8 PMID:16668188
Long, Joanne C.; Zhao, Wei; Rashotte, Aaron M.; Muday, Gloria K.; Huber, Steven C.; Brown, C. S. (Principal Investigator)
Maize (Zea mays) stem gravitropism involves differential elongation of cells within a highly specialized region, the stem internodal pulvinus. In the present study, we investigated factors that control gravitropic responses in this system. In the graviresponding pulvinus, hexose sugars (D-Glc and D-Fru) accumulated asymmetrically across the pulvinus. This correlated well with an asymmetric increase in acid invertase activity across the pulvinus. Northern analyses revealed asymmetric induction of one maize acid invertase gene, Ivr2, consistent with transcriptional regulation by gravistimulation. Several lines of evidence indicated that auxin redistribution, as a result of polar auxin transport, is necessary for gravity-stimulated Ivr2 transcript accumulation and differential cell elongation across the maize pulvinus. First, the auxin transport inhibitor, N-1-naphthylphthalamic acid, inhibited gravistimulated curvature and Ivr2 transcript accumulation. Second, a transient gradient of free indole-3-acetic acid (IAA) across the pulvinus was apparent shortly after initiation of gravistimulation. This temporarily free IAA gradient appears to be important for differential cell elongation and Ivr2 transcript accumulation. This is based on the observation that N-1-naphthylphthalamic acid will not inhibit gravitropic responses when applied to pulvinus tissue after the free IAA gradient peak has occurred. Third, IAA alone can stimulate Ivr2 transcript accumulation in non-gravistimulated pulvini. The gravity- and IAA-stimulated increase in Ivr2 transcripts was sensitive to the protein synthesis inhibitor, cycloheximide. Based on these results, a two-phase model describing possible relationships between gravitropic curvature, IAA redistribution, and Ivr2 expression is presented.
Landoni, Michela; Cerino Badone, Francesco; Haman, Nabil; Schiraldi, Alberto; Fessas, Dimitrios; Cesari, Valentina; Toschi, Ivan; Cremona, Roberta; Delogu, Chiara; Villa, Daniela; Cassani, Elena; Pilu, Roberto
Monogastric animals are unable to digest phytic acid, so it represents an antinutritional factor and also an environmental problem. One strategy to solve this problem is the utilization of low phytic acid (lpa) mutants that accumulate low levels of phytic P and high levels of free phosphate in the seeds; among the lpa maize mutants lpa1 exhibited the highest reduction of phytic acid in the seed. This study indicated that the low phytic acid mutations exerted pleiotropic effects not directly connected to the phytic acid pathway, such as on seed density, content of ions, and the antioxidant compounds present in the kernels. Furthermore some nutritional properties of the flour were altered by the lpa1 mutations, in particular lignin and protein content, while the starch does not seem to be modified as to the total amount and in the amylose/amylopectin ratio, but alterations were noticed in the structure and size of granules.
Deregulated expression of an Arabidopsis H(+)/Ca(2+) antiporter (sCAX1) in agricultural crops increases total calcium (Ca(2+)) but may result in yield losses due to Ca(2+) deficiency-like symptoms. Here we demonstrate that co-expression of a maize calreticulin (CRT, a Ca(2+) binding protein located ...
Casati, Paula; Walbot, Virginia
Microarray hybridization was used to assess acclimation responses to four UV regimes by near isogenic maize (Zea mays) lines varying in flavonoid content. We found that 355 of the 2,500 cDNAs tested were regulated by UV radiation in at least one genotype. Among these, 232 transcripts are assigned putative functions, whereas 123 encode unknown proteins. UV-B increased expression of stress response and ribosomal protein genes, whereas photosynthesis-associated genes were down-regulated; lines lacking UV-absorbing pigments had more dramatic responses than did lines with these pigments, confirming the shielding role of these compounds. Sunlight filtered to remove UV-B or UV-B plus UV-A resulted in significant expression changes in many genes not previously associated with UV responses. Some pathways regulated by UV radiation are shared with defense, salt, and oxidative stresses; however, UV-B radiation can activate additional pathways not shared with other stresses.
Hunter, Brenda G.; Beatty, Mary K.; Singletary, George W.; Hamaker, Bruce R.; Dilkes, Brian P.; Larkins, Brian A.; Jung, Rudolf
Maize starchy endosperm mutants have kernel phenotypes that include a brittle texture, susceptibility to insect pests, and inferior functional characteristics of products made from their flour. At least 18 such mutants have been identified, but only in the cases of opaque2 (o2) and floury2 (fl2), which affect different aspects of storage protein synthesis, is the molecular basis of the mutation known. To better understand the relationship between the phenotypes of these mutants and their biochemical bases, we characterized the protein and amino acid composition, as well as the mRNA transcript profiles, of nearly isogenic inbred lines of W64A o1, o2, o5, o9, o11, Mucuronate (Mc), Defective endosperm B30 (DeB30), and fl2. The largest reductions in zein protein synthesis occur in the W64A o2, DeB30, and fl2 mutants, which have ∼35 to 55% of the wild-type level of storage proteins. Zeins in W64A o5, o9, o11, and Mc are within 80 to 90% of the amount found in the wild type. Only in the cases of o5 and Mc were significant qualitative changes in zein synthesis observed. The pattern of gene expression in normal and mutant genotypes was assayed by profiling endosperm mRNA transcripts at 18 days after pollination with an Affymetrix GeneChip containing >1400 selected maize gene sequences. Compared with W64A sugary1, a mutant defective in starch synthesis, alterations in the gene expression patterns of the opaque mutants are very pleiotropic. Increased expression of genes associated with physiological stress, and the unfolded protein response, are common features of the opaque mutants. Based on global patterns of gene expression, these mutants were categorized in four phenotypic groups as follows: W64A+ and o1; o2; o5/o9/o11; and Mc and fl2. PMID:12368507
de Luis, Ruth; Lavilla, María; Sánchez, Lourdes; Calvo, Miguel; Pérez, María D
The aim of this work was to study the in vitro digestion of Cry1A(b) protein by pepsin. To perform this work, a protein fraction purified from transgenic maize by immunoadsorption was employed. The undigested fraction showed several bands of molecular weight ranging between 14 and 70 kDa when assayed by SDS-PAGE. These bands were identified as corresponding to Cry1A(b) protein by immunochemical techniques and mass spectrometry. The rate of degradation of the purified fraction by pepsin estimated by ELISA was found to be about 75% within 30 min, and the protein concentration remained constant up to 4 h. In all treated samples, the full-length protein and fragments present in Cry1A(b) fraction were absent and peptides of less than 8.5 kDa were mainly found by SDS-PAGE and mass spectrometry. These peptides did not react with antiserum against Cry1A(b) protein by Western blotting. These results suggest that Cry1A(b) fraction purified from transgenic maize is rapidly and extensively degraded by pepsin, giving peptides of low molecular mass.
Kobayashi, H.; Bogorad, L.; Miles, C.D.
In order to gain a better understanding of the interaction between the chloroplast and nuclear genomes in controlling the expression of plastid genes and the biosynthesis of chloroplast proteins, maize (Zea mays) nuclear gene mutant hcf*-38, in which ..cap alpha.. and ..beta.. subunits of coupling factor one (CF/sub 1/) are almost completely missing was studied. The mutant possesses all the other subunits of CF/sub 1/ but several peptides of photosystem II are present in reduced amounts. A competitive hybridization experiment showed the presence of the same plastid mRNA species in mutant and wild-type plants except for slightly lower levels of some transcripts in the mutant. Northern hybridization and dot blot hybridization experiments showed the features of transcripts for ..cap alpha.. and ..beta.. subunits of CF/sub 1/ in the mutant to be similar to those in the wild-type maize although their levels are somewhat lower in the mutant. In vivo and in organello protein labeling experiments with L-(/sup 35/S)Met have shown that ..cap alpha.. and ..beta.. subunits of CF/sub 1/ are synthesized, assembled into CF/sub 1/, and probably associated with thylakoid membranes in mutant plants. It is concluded that they are subsequently degraded.
Cruzan, Mitchell B.; Rosenstiel, Todd N.
The cultivation of genetically engineered Bacillus thuringiensis toxin-expressing (Bt) maize continues to increase worldwide, yet the effects of Bt crops on arbuscular mycorrhizal fungi (AMF) in soil are poorly understood. In this field experiment, we investigated the impact of seven different genotypes of Bt maize and five corresponding non-Bt parental cultivars on AMF and evaluated plant growth responses at three different physiological time points. Plants were harvested 60 days (active growth), 90 days (tasseling and starting to produce ears), and 130 days (maturity) after sowing, and data on plant growth responses and percent AMF colonization of roots at each harvest were collected. Spore abundance and diversity were also evaluated at the beginning and end of the field season to determine whether the cultivation of Bt maize had a negative effect on AMF propagules in the soil. Plant growth and AMF colonization did not differ between Bt and non-Bt maize at any harvest period, but AMF colonization was positively correlated with leaf chlorophyll content at the 130-day harvest. Cultivation of Bt maize had no effect on spore abundance and diversity in Bt versus non-Bt plots over one field season. Plot had the most significant effect on total spore counts, indicating spatial heterogeneity in the field. Although previous greenhouse studies demonstrated that AMF colonization was lower in some Bt maize lines, our field study did not yield the same results, suggesting that the cultivation of Bt maize may not have an impact on AMF in the soil ecosystem under field conditions. PMID:23624473
Kyozuka, J; Olive, M; Peacock, W J; Dennis, E S; Shimamoto, K
To define the regions of the maize alcohol dehydrogenase 1 (Adh1) promoter that confer tissue-specific expression, a series of 5' promoter deletions and substitution mutations were linked to the Escherichia coli beta-glucuronidase A (uidA) reporter gene and introduced into rice plants. A region between -140 and -99 not only conferred anaerobically inducible expression in the roots of transgenic plants but was also required for expression in the root cap, embryo, and in endosperm under aerobic conditions. GC-rich (GC-1, GC-2, and GC-3) or GT-rich (GT-1 and GT-2) sequence motifs in this region were necessary for expression in these tissues, as they were in anaerobic expression. Expression in the root cap under aerobic conditions required all the GC- and GT-rich motifs. The GT-1, GC-1, GC-2, and GC-3 motifs, and to a lesser extent the GT-2 motif, were also required for anaerobic responsiveness in rice roots. All elements except the GC-3 motif were needed for endosperm-specific expression. The GC-2 motif and perhaps the GT-1 motif appeared to be the only elements required for high-level expression in the embryos of rice seeds. Promoter regions important for shoot-, embryo-, and pollen-specific expression were proximal to -99, and nucleotides required for shoot-specific expression occurred between positions -72 and -43. Pollen-specific expression required a sequence element outside the promoter region, between +54 and +106 of the untranslated leader, as well as a silencer element in the promoter between -72 and -43. PMID:8061518
Xin, Mingming; Yang, Ruolin; Li, Guosheng; Chen, Hao; Laurie, John; Ma, Chuang; Wang, Dongfang; Yao, Yingyin; Larkins, Brian A; Sun, Qixin; Yadegari, Ramin; Wang, Xiangfeng; Ni, Zhongfu
In angiosperms, the endosperm provides nutrients for embryogenesis and seed germination and is the primary tissue where gene imprinting occurs. To identify the imprintome of early developing maize (Zea mays) endosperm, we performed high-throughput transcriptome sequencing of whole kernels at 0, 3, and 5 d after pollination (DAP) and endosperms at 7, 10, and 15 DAP, using B73 by Mo17 reciprocal crosses. We observed gradually increased expression of paternal transcripts in 3- and 5-DAP kernels. In 7-DAP endosperm, the majority of the genes tested reached a 2:1 maternal versus paternal ratio, suggesting that paternal genes are nearly fully activated by 7 DAP. A total of 116, 234, and 63 genes exhibiting parent-specific expression were identified at 7, 10, and 15 DAP, respectively. The largest proportion of paternally expressed genes was at 7 DAP, mainly due to the significantly deviated parental allele expression ratio of these genes at this stage, while nearly 80% of the maternally expressed genes (MEGs) were specific to 10 DAP and were primarily attributed to sharply increased expression levels compared with the other stages. Gene ontology enrichment analysis of the imprinted genes suggested that 10-DAP endosperm-specific MEGs are involved in nutrient uptake and allocation and the auxin signaling pathway, coincident with the onset of starch and storage protein accumulation.
Broothaerts, Wim; Corbisier, Philippe; Schimmel, Heinz; Trapmann, Stefanie; Vincent, Sandra; Emons, Hendrik
The real-time PCR methods recommended in the European Union for the quantitation of genetically modified (GM) maize events NK603, GA21, and MON 863 measure the number of copies of the GM event in relation to those of the maize-specific adh1 reference gene. The study reported here revealed that the targeted 70 base pair adh1 region exhibits a single nucleotide polymorphism (SNP839) that hampers the binding of the reverse primer used in the adh1 detection method. Partial fragments of the adh1-A and adh1-F allele were cloned. By allele-specific real-time PCR, it was shown that SNP839 corresponds to a common allelic polymorphism in maize. As a result, the quantitation of the GM maize events mentioned is positively or negatively biased, depending on the adh1 genotype of sample and calibrant. Therefore, it is proposed to revise the quantitative detection methods for NK603, GA21, and MON 863 maize.
Shindo, Yoichiro; Kuribara, Hideo; Matsuoka, Takeshi; Futo, Satoshi; Sawada, Chihiro; Shono, Jinji; Akiyama, Hiroshi; Goda, Yukihiro; Toyoda, Masatake; Hino, Akihiro
Novel analytical methods based on real-time quantitative polymerase chain reactions by use of new reference molecules were validated in interlaboratory studies for the quantitation of genetically modified (GM) maize and soy. More than 13 laboratories from Japan, Korea, and the United States participated in the studies. The interlaboratory studies included 2 separate stages: (1) measurement tests of coefficient values, the ratio of recombinant DNA (r-DNA) sequence, and endogenous DNA sequence in the seeds of GM maize and GM soy; and (2) blind tests with 6 pairs of maize and soy samples, including different levels of GM maize or GM soy. Test results showed that the methods are applicable to the specific quantitation of the 5 lines of GM maize and one line of GM soy. After statistical treatment to remove outliers, the repeatability and reproducibility of these methods at a level of 5.0% were <13.7 and 15.9%, respectively. The quantitation limits of the methods were 0.50% for Bt11, T25, and MON810, and 0.10% for GA21, Event176, and Roundup Ready soy. The results of blind tests showed that the numerical information obtained from these methods will contribute to practical analyses for labeling systems of GM crops.
Shrestha, Hari K; Hwu, Kae-Kang; Wang, Shu-Jen; Liu, Li-Fei; Chang, Men-Chi
To fulfill labeling and traceability requirement of genetically modified (GM) maize for trade and regulation, it is essential to develop an event-specific detection method for monitoring the presence of transgenes. In pursuit of this purpose, we systematically optimized and established a combined event- and construct-specific multiplex polymerase chain reaction (mPCR) technique for simultaneous detection of 8 GM maize lines. Altogether 9 sets of primers were designed, including six that were event-specific for Event176, Bt11, TC1507, NK603, MON863, and Mon810; two that were construct-specific for T25 and GA21, and one for an endogenous zein gene. The transgene in each GM maize line and the endogenous zein gene could be clearly detected and distinguished according to the different sizes of PCR amplicons. The limit of detection (LOD) was approximately 0.25% (v/v), although the detection can be as sensitive as 0.1% as demonstrated by the International Seed Testing Association (ISTA) proficiency test. This study further improves the current PCR-based detection method for GM maize. The method can be used in an easy, sensitive, and cost and time effective way for the identification and quality screening of a specific GM maize line.
Yue, Guidong; Zhuang, Yunlong; Li, Zhaoxia; Sun, Li; Zhang, Juren
The whole-genomic gene-expression changes of maize (Zea mays L.) plants in response to water-deficit stress at the heading stage have not been previously studied. The present work utilized a maize oligonucleotide array ('57K', approximately 57000 sequences; http://www.maizearray.org/) representing more than 30000 unique genes, to profile transcriptome changes in maize leaves subjected to 1d (day) and 7d water-deficit stress. After 1d and 7d water-stress treatment, 195 and 1008 differential genes were identified respectively. One-third of 1d-water-stress-induced genes had known or putative functions in various cellular signalling pathways, indicating that signal-transduction-related genes play important roles in the early responses of maize leaves to water stress. The 7d-stress-regulated genes were involved in a broad range of cellular and biochemical activities. The most notable genes may function in compatible osmolyte metabolism, particularly in proline, sucrose, trehalose and raffinose metabolism in the leaves. The present study provided a valuable starting point for further elucidation of molecular mechanisms in the drought tolerance of maize plants.
Palencia, Edwin Rene; Glenn, Anthony Elbie; Hinton, Dorothy Mae; Bacon, Charles Wilson
Aspergillus niger and Aspergillus carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspergilli produce important mycotoxins, ochratoxins A, and the fumonisins. To facilitate the study of the black aspergilli-maize interactions with maize during the early stages of infections, we developed a method that used the enhanced yellow fluorescent protein (eYFP) and the monomeric red fluorescent protein (mRFP1) to transform A. niger and A. carbonarius, respectively. The results were constitutive expressions of the fluorescent genes that were stable in the cytoplasms of hyphae and conidia under natural environmental conditions. The hyphal in planta distribution in 21-day-old seedlings of maize were similar wild type and transformants of A. niger and A. carbonarius. The in planta studies indicated that both wild type and transformants internally colonized leaf, stem and root tissues of maize seedlings, without any visible disease symptoms. Yellow and red fluorescent strains were capable of invading epidermal cells of maize roots intercellularly within the first 3 days after inoculation, but intracellular hyphal growth was more evident after 7 days of inoculation. We also tested the capacity of fluorescent transformants to produce ochratoxin A and the results with A. carbonarius showed that this transgenic strain produced similar concentrations of this secondary metabolite. This is the first report on the in planta expression of fluorescent proteins that should be useful to study the internal plant colonization patterns of two ochratoxigenic species in the Aspergillus section Nigri.
Juglone (5-hydroxy-1,4-naphthoquinone) has been identified in organs of many plant species within Juglandaceae family. This secondary metabolite is considered as a highly bioactive substance that functions as direct oxidant stimulating the production of reactive oxygen species (ROS) in acceptor plants. Glutathione transferases (GSTs, E.C.188.8.131.52) represent an important group of cytoprotective enzymes participating in detoxification of xenobiotics and limiting oxidative damages of cellular macromolecules. The purpose of this study was to investigate the impact of tested allelochemical on growth and development of maize (Zea mays L.) seedlings. Furthermore, the effect of juglone-induced oxidative stress on glutathione transferase (GstI) gene expression patterns in maize seedlings was recorded. It was revealed that 4-day juglone treatment significantly stimulated the transcriptional activity of GstI in maize seedlings compared to control plants. By contrast, at the 6th and 8th day of experiments the expression gene responses were slightly lower as compared with non-stressed seedlings. Additionally, the specific gene expression profiles, as well as the inhibition of primary roots and coleoptile elongation were proportional to juglone concentrations. In conclusion, the results provide strong molecular evidence that allelopathic influence of juglone on growth and development of maize seedlings may be relevant with an induction of oxidative stress in acceptor plants. PMID:22174645
Li, Dandan; Zhang, Xiwen; Tian, Yaoqi
Biosynthesis of octenyl succinic anhydride (OSA) starch was investigated using ionic liquids (ILs) as reaction media. Waxy maize starch was pretreated in 1-butyl-3-methylimidazolium chlorine and then esterified with OSA in 1-octyl-3-methylimidazolium nitrate by using Novozyme 435 as catalyst. The degree of substitution of OSA starch reached 0.0130 with 5 wt% starch concentration and 1 wt% lipase dosage based on ILs weight at 50 °C for 3h. The formation of OSA starch was confirmed by fourier transform infrared spectroscopy. Scanning electron microscopy and X-ray diffraction revealed that the morphology and crystal structure of starch were significantly destroyed. Thermogravimetric analysis showed that esterification decreased the thermal stability of starch. The successful lipase-catalyzed synthesis of OSA starch in ILs suggests that ILs are potential replacement of traditional organic solvents for starch ester biosynthesis.
Paulis, J W; Bietz, J A; Bogyo, T P; Darrah, L L; Zuber, M S
Many maize (Zea mays L.) mutant genes exist. Some affect protein content or composition, while others modify carbohydrates or kernel phenotype. In doublemutant lines, two mutant genes are present. We know little about interactions of such genes, however. We therefore examined a normal maize inbred, B37, 10 near-isogenic single mutants and 46 double mutants to analyze quantitative effects on alcohol-soluble endosperm proteins. Proteins were extracted with 70% ethanol0.5% sodium acetate-5% mercaptoethanol, and fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC). Early peaks were alcohol-soluble glutelin (ASG) subunits, while late peaks contained zein. Results were quantified and statistically analyzed. In many double mutants, protein compositions differed significantly from averages of compositions of corresponding single mutants. For example, a high-methionine, water-insoluble ASG is absent when the opaque-2 (o2) gene combines with shrunken-1 (sh1) or surgary-1 (su1). Another water-insoluble ASG nearly doubled when floury-2 (fl2) andsu1 combined. A high-proline, high-histidine, water-soluble ASG nearly doubled in combinations offl2 witho2,su1 and sugary-2 (su2). Zein was about half its expected value wheno2 combined with amylose-extender (ae), floury-1 (fl1), soft-starch (h),sh1 andsu1. Thus, rapid protein extraction and quantitative RP-HPLC showed major new epistatic and synergistic effects of several mutant genes on protein composition. Unexpectedly, these effects often involve genes that primarily affect starch composition or kernel phenotype. Alcohol-soluble proteins often vary in amount, as ino2 lines. They also differ in nutritional value. Thus, RP-HPLC analysis of these proteins can identify nutritionally superior genotypes, and may help explain the basis of such quality.
Dobnik, David; Spilsberg, Bjørn; Bogožalec Košir, Alexandra; Holst-Jensen, Arne; Žel, Jana
Presence of genetically modified organisms (GMO) in food and feed products is regulated in many countries. The European Union (EU) has implemented a threshold for labeling of products containing more than 0.9% of authorized GMOs per ingredient. As the number of GMOs has increased over time, standard-curve based simplex quantitative polymerase chain reaction (qPCR) analyses are no longer sufficiently cost-effective, despite widespread use of initial PCR based screenings. Newly developed GMO detection methods, also multiplex methods, are mostly focused on screening and detection but not quantification. On the basis of droplet digital PCR (ddPCR) technology, multiplex assays for quantification of all 12 EU authorized GM maize lines (per April first 2015) were developed. Because of high sequence similarity of some of the 12 GM targets, two separate multiplex assays were needed. In both assays (4-plex and 10-plex), the transgenes were labeled with one fluorescence reporter and the endogene with another (GMO concentration = transgene/endogene ratio). It was shown that both multiplex assays produce specific results and that performance parameters such as limit of quantification, repeatability, and trueness comply with international recommendations for GMO quantification methods. Moreover, for samples containing GMOs, the throughput and cost-effectiveness is significantly improved compared to qPCR. Thus, it was concluded that the multiplex ddPCR assays could be applied for routine quantification of 12 EU authorized GM maize lines. In case of new authorizations, the events can easily be added to the existing multiplex assays. The presented principle of quantitative multiplexing can be applied to any other domain.
Cankar, Katarina; Chauvensy-Ancel, Valérie; Fortabat, Marie-Noelle; Gruden, Kristina; Kobilinsky, André; Zel, Jana; Bertheau, Yves
Detection of nonauthorized genetically modified organisms (GMOs) has always presented an analytical challenge because the complete sequence data needed to detect them are generally unavailable although sequence similarity to known GMOs can be expected. A new approach, differential quantitative polymerase chain reaction (PCR), for detection of nonauthorized GMOs is presented here. This method is based on the presence of several common elements (e.g., promoter, genes of interest) in different GMOs. A statistical model was developed to study the difference between the number of molecules of such a common sequence and the number of molecules identifying the approved GMO (as determined by border-fragment-based PCR) and the donor organism of the common sequence. When this difference differs statistically from zero, the presence of a nonauthorized GMO can be inferred. The interest and scope of such an approach were tested on a case study of different proportions of genetically modified maize events, with the P35S promoter as the Cauliflower Mosaic Virus common sequence. The presence of a nonauthorized GMO was successfully detected in the mixtures analyzed and in the presence of (donor organism of P35S promoter). This method could be easily transposed to other common GMO sequences and other species and is applicable to other detection areas such as microbiology.
Takabatake, Reona; Masubuchi, Tomoko; Futo, Satoshi; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Teshima, Reiko; Kurashima, Takeyo; Mano, Junichi; Kitta, Kazumi
A novel real-time PCR-based analytical method was developed for the event-specific quantification of a genetically modified (GM) maize event, MIR162. We first prepared a standard plasmid for MIR162 quantification. The conversion factor (Cf) required to calculate the genetically modified organism (GMO) amount was empirically determined for two real-time PCR instruments, the Applied Biosystems 7900HT (ABI7900) and the Applied Biosystems 7500 (ABI7500) for which the determined Cf values were 0.697 and 0.635, respectively. To validate the developed method, a blind test was carried out in an interlaboratory study. The trueness and precision were evaluated as the bias and reproducibility of relative standard deviation (RSDr). The determined biases were less than 25% and the RSDr values were less than 20% at all evaluated concentrations. These results suggested that the limit of quantitation of the method was 0.5%, and that the developed method would thus be suitable for practical analyses for the detection and quantification of MIR162.
Ding, Xupo; Yang, Min; Huang, Huichuan; Chuan, Youcong; He, Xiahong; Li, Chengyun; Zhu, Youyong; Zhu, Shusheng
Plant disease can be effectively suppressed in intercropping systems. Our previous study demonstrated that neighboring maize plants can restrict the spread of soil-borne pathogens of pepper plants by secreting defense compounds into the soil. However, whether maize plant can receive benefits from its neighboring pepper plants in an intercropping system is little attention. We examined the effects of maize roots treated with elicitors from the pepper pathogen Phytophthora capsici and pepper root exudates on the synthesis of 1,4-benzoxazine-3-ones (BXs), the expression of defense-related genes in maize, and their ability to alleviate the severity of southern corn leaf blight (SCLB) caused by Bipolaris maydis. We found that SCLB was significantly reduced after the above treatments. The contents of 1,4-benzoxazine-3-ones (BXs: DIBOA, DIMBOA, and MBOA) and the expression levels of BX synthesis and defense genes in maize roots and shoots were up-regulated. DIMBOA and MBOA effectively inhibited the mycelium growth of Bipolaris maydis at physiological concentrations in maize shoots. Further studies suggested that the defense related pathways or genes in maize roots and shoots were activated by elicitors from the P. capsici or pepper root exudates. In conclusion, maize increased the levels of BXs and defense gene expression both in roots and shoots after being triggered by root exudates and pathogen from neighboring pepper plants, eventually enhancing its resistance.
Ding, Xupo; Yang, Min; Huang, Huichuan; Chuan, Youcong; He, Xiahong; Li, Chengyun; Zhu, Youyong; Zhu, Shusheng
Plant disease can be effectively suppressed in intercropping systems. Our previous study demonstrated that neighboring maize plants can restrict the spread of soil-borne pathogens of pepper plants by secreting defense compounds into the soil. However, whether maize plant can receive benefits from its neighboring pepper plants in an intercropping system is little attention. We examined the effects of maize roots treated with elicitors from the pepper pathogen Phytophthora capsici and pepper root exudates on the synthesis of 1,4-benzoxazine-3-ones (BXs), the expression of defense-related genes in maize, and their ability to alleviate the severity of southern corn leaf blight (SCLB) caused by Bipolaris maydis. We found that SCLB was significantly reduced after the above treatments. The contents of 1,4-benzoxazine-3-ones (BXs: DIBOA, DIMBOA, and MBOA) and the expression levels of BX synthesis and defense genes in maize roots and shoots were up-regulated. DIMBOA and MBOA effectively inhibited the mycelium growth of Bipolaris maydis at physiological concentrations in maize shoots. Further studies suggested that the defense related pathways or genes in maize roots and shoots were activated by elicitors from the P. capsici or pepper root exudates. In conclusion, maize increased the levels of BXs and defense gene expression both in roots and shoots after being triggered by root exudates and pathogen from neighboring pepper plants, eventually enhancing its resistance. PMID:26528303
Marcon, Caroline; Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Baldauf, Jutta A; Altrogge, Lena; Opitz, Nina; Lanz, Christa; Schoof, Heiko; Nettleton, Dan; Piepho, Hans-Peter; Hochholdinger, Frank
Heterosis is the superior performance of F1 hybrids compared with their homozygous, genetically distinct parents. In this study, we monitored the transcriptomic divergence of the maize (Zea mays) inbred lines B73 and Mo17 and their reciprocal F1 hybrid progeny in primary roots under control and water deficit conditions simulated by polyethylene glycol treatment. Single-parent expression (SPE) of genes is an extreme instance of gene expression complementation, in which genes are active in only one of two parents but are expressed in both reciprocal hybrids. In this study, 1,997 genes only expressed in B73 and 2,024 genes only expressed in Mo17 displayed SPE complementation under control and water deficit conditions. As a consequence, the number of active genes in hybrids exceeded the number of active genes in the parental inbred lines significantly independent of treatment. SPE patterns were substantially more stable to expression changes by water deficit treatment than other genotype-specific expression profiles. While, on average, 75% of all SPE patterns were not altered in response to polyethylene glycol treatment, only 17% of the remaining genotype-specific expression patterns were not changed by water deficit. Nonsyntenic genes that lack syntenic orthologs in other grass species, and thus evolved late in the grass lineage, were significantly overrepresented among SPE genes. Hence, the significant overrepresentation of nonsyntenic genes among SPE patterns and their stability under water limitation might suggest a function of these genes during the early developmental manifestation of heterosis under fluctuating environmental conditions in hybrid progeny of the inbred lines B73 and Mo17.
The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants. PMID:24722734
The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants.
Reduced forms of ascorbate (AsA) and glutathione (GSH) are among the most important non-enzymatic foliar antioxidants in maize (Zea mays L.). The survey was aimed to evaluate impact of bird cherry-oat aphid (Rhopalosiphum padi L.) or grain aphid (Sitobion avenae F.) herbivory on expression of genes related to ascorbate-glutathione (AsA-GSH) cycle in seedlings of six maize varieties (Ambrozja, Nana, Tasty Sweet, Touran, Waza, Złota Karłowa), differing in resistance to the cereal aphids. Relative expression of sixteen maize genes encoding isoenzymes of ascorbate peroxidase (APX1, APX2, APX3, APX4, APX5, APX6, APX7), monodehydroascorbate reductase (MDHAR1, MDHAR2, MDHAR3, MDHAR4), dehydroascorbate reductase (DHAR1, DHAR2, DHAR3) and glutathione reductase (GR1, GR2) was quantified. Furthermore, effect of hemipterans' attack on activity of APX, MDHAR, DHAR and GR enzymes, and the content of reduced and oxidized ascorbate and glutathione in maize plants were assessed. Seedling leaves of more resistant Z. mays varieties responded higher elevations in abundance of target transcripts. In addition, earlier and stronger aphid-triggered changes in activity of APX, MDHAR, DHAR and GR enzymes, and greater modulations in amount of the analyzed antioxidative metabolites were detected in foliar tissues of highly resistant Ambrozja genotype in relation to susceptible Tasty Sweet plants.
Reduced forms of ascorbate (AsA) and glutathione (GSH) are among the most important non-enzymatic foliar antioxidants in maize (Zea mays L.). The survey was aimed to evaluate impact of bird cherry-oat aphid (Rhopalosiphum padi L.) or grain aphid (Sitobion avenae F.) herbivory on expression of genes related to ascorbate-glutathione (AsA-GSH) cycle in seedlings of six maize varieties (Ambrozja, Nana, Tasty Sweet, Touran, Waza, Złota Karłowa), differing in resistance to the cereal aphids. Relative expression of sixteen maize genes encoding isoenzymes of ascorbate peroxidase (APX1, APX2, APX3, APX4, APX5, APX6, APX7), monodehydroascorbate reductase (MDHAR1, MDHAR2, MDHAR3, MDHAR4), dehydroascorbate reductase (DHAR1, DHAR2, DHAR3) and glutathione reductase (GR1, GR2) was quantified. Furthermore, effect of hemipterans’ attack on activity of APX, MDHAR, DHAR and GR enzymes, and the content of reduced and oxidized ascorbate and glutathione in maize plants were assessed. Seedling leaves of more resistant Z. mays varieties responded higher elevations in abundance of target transcripts. In addition, earlier and stronger aphid-triggered changes in activity of APX, MDHAR, DHAR and GR enzymes, and greater modulations in amount of the analyzed antioxidative metabolites were detected in foliar tissues of highly resistant Ambrozja genotype in relation to susceptible Tasty Sweet plants. PMID:26907270
The fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial yield losses annually throughout the western hemisphere. To learn more about the molecular regulation of pathogenesis in C. zeae-maydis, we generated a collection of expressed sequence tags (ESTs) and...
Yoon, Sangwoong; Devaiah, Shivakumar P; Choi, Seo-eun; Bray, Jeff; Love, Robert; Lane, Jeffrey; Drees, Carol; Howard, John H; Hood, Elizabeth E
Plant cell wall degradation into fermentable sugars by cellulases is one of the greatest barriers to biofuel production. Expansin protein loosens the plant cell wall by opening up the complex of cellulose microfibrils and polysaccharide matrix components thereby increasing its accessibility to cellulases. We over-expressed cucumber expansin in maize kernels to produce enough protein to assess its potential to serve as an industrial enzyme for applications particularly in biomass conversion. We used the globulin-1 embryo-preferred promoter to express the cucumber expansin gene in maize seed. Expansin protein was targeted to one of three sub-cellular locations: the cell wall, the vacuole, or the endoplasmic reticulum (ER). To assess the level of expansin accumulation in seeds of transgenic kernels, a high throughput expansin assay was developed. The highest expressing plants were chosen and enriched crude expansin extract from those plants was tested for synergistic effects with cellulase on several lignocellulosic substrates. Activity of recombinant cucumber expansin from transgenic kernels was confirmed on these pretreated substrates. The best transgenic lines (ER-targeted) can now be used for breeding to increase expansin expression for use in the biomass conversion industry. Results of these experiments show the success of expansin over-expression and accumulation in transgenic maize seed without negative impact on growth and development and confirm its synergistic effect with cellulase on deconstruction of complex cell wall substrates.
Lu, Min; Sun, Qing-Peng; Zhang, Deng-Feng; Wang, Tian-Yu; Pan, Jin-Bao
NAC proteins are plant-specific transcription factors that play essential roles in plant development and various abiotic stress responses. A comprehensive analysis of maize NAC genes was performed in this study. A total of 157 non-redundant maize NAC genes including seven membrane-bound members were identified and found to be unevenly distributed on 10 maize chromosomes. Motif composition analysis indicated that the maize NAC proteins share three relatively conserved motifs in the NAC domain within the N-terminal region. Phylogenetic analysis of 157 maize NAC proteins accompanied by 117 NAC proteins from Arabidopsis and 151 from rice were presented. The NAC proteins evaluated were divided into two large groups including 18 subgroups. Gene duplication analysis indicated that gene loss occurred during maize evolution. Seven NAC members that belong to the same clade of maize NAC domain genes were isolated, and overlapping expression patterns were observed under various abiotic stresses, including low temperature, high salinity and dehydration, and phytohormone abscisic acid treatments. This suggested that NAC members function as stress-responsive transcription factors in ABA-dependent signaling pathways. Relatively higher expression levels of these selected maize NAC genes were detected in roots. The stress responsive NAC genes may have applications in molecular breeding to improve crop stress tolerance.
Waters, Amanda J; Makarevitch, Irina; Noshay, Jaclyn; Burghardt, Liana T; Hirsch, Candice N; Hirsch, Cory D; Springer, Nathan M
Plants respond to abiotic stress through a variety of physiological, biochemical, and transcriptional mechanisms. Many genes exhibit altered levels of expression in response to abiotic stress, which requires concerted action of both cis- and trans-regulatory features. In order to study the variability in transcriptome response to abiotic stress, RNA sequencing was performed using 14-day-old maize seedlings of inbreds B73, Mo17, Oh43, PH207 and B37 under control, cold and heat conditions. Large numbers of genes that responded differentially to stress between parental inbred lines were identified. RNA sequencing was also performed on similar tissues of the F1 hybrids produced by crossing B73 and each of the three other inbred lines. By evaluating allele-specific transcript abundance in the F1 hybrids, we were able to measure the abundance of cis- and trans-regulatory variation between genotypes for both steady-state and stress-responsive expression differences. Although examples of trans-regulatory variation were observed, cis-regulatory variation was more common for both steady-state and stress-responsive expression differences. The genes with cis-allelic variation for response to cold or heat stress provided an opportunity to study the basis for regulatory diversity.
Cao, Xiuling; Lu, Yingui; Di, Dianping; Zhang, Zhiyan; Liu, He; Tian, Lanzhi; Zhang, Aihong; Zhang, Yanjing; Shi, Lindan; Guo, Bihong; Xu, Jin; Duan, Xifei; Wang, Xianbing; Han, Chenggui; Miao, Hongqin; Yu, Jialin; Li, Dawei
Maize rough dwarf disease (MRDD), caused by several Fijiviruses in the family Reoviridae, is a global disease that is responsible for substantial yield losses in maize. Although some maize germplasm have low levels of polygenic resistance to MRDD, highly resistant cultivated varieties are not available for agronomic field production in China. In this work, we have generated transgenic maize lines that constitutively express rnc70, a mutant E. coli dsRNA-specific endoribonuclease gene. Transgenic lines were propagated and screened under field conditions for 12 generations. During three years of evaluations, two transgenic lines and their progeny were challenged with Rice black-streaked dwarf virus (RBSDV), the causal agent of MRDD in China, and these plants exhibited reduced levels of disease severity. In two normal years of MRDD abundance, both lines were more resistant than non-transgenic plants. Even in the most serious MRDD year, six out of seven progeny from one line were resistant, whereas non-transgenic plants were highly susceptible. Molecular approaches in the T12 generation revealed that the rnc70 transgene was integrated and expressed stably in transgenic lines. Under artificial conditions permitting heavy virus inoculation, the T12 progeny of two highly resistant lines had a reduced incidence of MRDD and accumulation of RBSDV in infected plants. In addition, we confirmed that the RNC70 protein could bind directly to RBSDV dsRNA in vitro. Overall, our data show that RNC70-mediated resistance in transgenic maize can provide efficient protection against dsRNA virus infection.
Liseron-Monfils, Christophe; Bi, Yong-Mei; Downs, Gregory S; Wu, Wenqing; Signorelli, Tara; Lu, Guangwen; Chen, Xi; Bondo, Eddie; Zhu, Tong; Lukens, Lewis N; Colasanti, Joseph; Rothstein, Steven J; Raizada, Manish N
Nitrogen is considered the most limiting nutrient for maize (Zea mays L.), but there is limited understanding of the regulation of nitrogen-related genes during maize development. An Affymetrix 82K maize array was used to analyze the expression of ≤ 46 unique nitrogen uptake and assimilation probes in 50 maize tissues from seedling emergence to 31 d after pollination. Four nitrogen-related expression clusters were identified in roots and shoots corresponding to, or overlapping, juvenile, adult, and reproductive phases of development. Quantitative real time PCR data was consistent with the existence of these distinct expression clusters. Promoters corresponding to each cluster were screened for over-represented cis-acting elements. The 8-bp distal motif of the Arabidopsis 43-bp nitrogen response element (NRE) was over-represented in nitrogen-related maize gene promoters. This conserved motif, referred to here as NRE43-d8, was previously shown to be critical for nitrate-activated transcription of nitrate reductase (NIA1) and nitrite reductase (NIR1) by the NIN-LIKE PROTEIN 6 (NLP6) in Arabidopsis. Here, NRE43-d8 was over-represented in the promoters of maize nitrate and ammonium transporter genes, specifically those that showed peak expression during early-stage vegetative development. This result predicts an expansion of the NRE-NLP6 regulon and suggests that it may have a developmental component in maize. We also report leaf expression of putative orthologs of nitrite transporters (NiTR1), a transporter not previously reported in maize. We conclude by discussing how each of the four transcriptional modules may be responsible for the different nitrogen uptake and assimilation requirements of leaves and roots at different stages of maize development.
Salvo, Stella A. G. D.; Hirsch, Candice N.; Buell, C. Robin; Kaeppler, Shawn M.; Kaeppler, Heidi F.
Embryogenic tissue culture systems are utilized in propagation and genetic engineering of crop plants, but applications are limited by genotype-dependent culture response. To date, few genes necessary for embryogenic callus formation have been identified or characterized. The goal of this research was to enhance our understanding of gene expression during maize embryogenic tissue culture initiation. In this study, we highlight the expression of candidate genes that have been previously regarded in the literature as having important roles in somatic embryogenesis. We utilized RNA based sequencing (RNA-seq) to characterize the transcriptome of immature embryo explants of the highly embryogenic and regenerable maize genotype A188 at 0, 24, 36, 48, and 72 hours after placement of explants on tissue culture initiation medium. Genes annotated as functioning in stress response, such as glutathione-S-transferases and germin-like proteins, and genes involved with hormone transport, such as PINFORMED, increased in expression over 8-fold in the study. Maize genes with high sequence similarity to genes previously described in the initiation of embryogenic cultures, such as transcription factors BABY BOOM, LEAFY COTYLEDON, and AGAMOUS, and important receptor-like kinases such as SOMATIC EMBRYOGENESIS RECEPTOR LIKE KINASES and CLAVATA, were also expressed in this time course study. By combining results from whole genome transcriptome analysis with an in depth review of key genes that play a role in the onset of embryogenesis, we propose a model of coordinated expression of somatic embryogenesis-related genes, providing an improved understanding of genomic factors involved in the early steps of embryogenic culture initiation in maize and other plant species. PMID:25356773
Dante, Ricardo A; Sabelli, Paolo A; Nguyen, Hong N; Leiva-Neto, João T; Tao, Yumin; Lowe, Keith S; Hoerster, George J; Gordon-Kamm, William J; Jung, Rudolf; Larkins, Brian A
Endosperm development in maize (Zea mays L.) and related cereals comprises a cell proliferation stage followed by a period of rapid growth coupled to endoreduplication. Regulation of the cell cycle in developing endosperm is poorly understood. We have characterized various subunits of cyclin-dependent kinase (CDK) complexes, master cell cycle regulators in all eukaryotes. A-, B-, and D-type cyclins as well as A- and B-type cyclin-dependent kinases were characterized with respect to their RNA and protein expression profiles. Two main patterns were identified: one showing expression throughout endosperm development, and another characterized by a sharp down-regulation with the onset of endoreduplication. Cyclin CYCB1;3 and CYCD2;1 proteins were distributed in the cytoplasm and nucleus of cells throughout the endosperm, while cyclin CYCD5 protein was localized in the cytoplasm of peripheral cells. CDKB1;1 expression was strongly associated with cell proliferation. Expression and cyclin-binding patterns suggested that CDKA;1 and CDKA;3 are at least partially redundant. The kinase activity associated with the cyclin CYCA1 was highest during the mitotic stage of development, while that associated with CYCB1;3, CYCD2;1 and CYCD5 peaked at the mitosis-to-endoreduplication transition. A-, B- and D-type cyclins were more resistant to proteasome-dependent degradation in endoreduplicating than in mitotic endosperm extracts. These results indicated that endosperm development is characterized by differential expression and activity of specific cyclins and CDKs, and suggested that endoreduplication is associated with reduced cyclin proteolysis via the ubiquitin-proteasome pathway.
The ultimate aim of our work is to understand how a regulatory gene produces a specific pattern of gene expression during plant development. Our model is the P-wr gene of maize, which produces a distinctive pattern of pigmentation of maize floral organs. We are investigating this system using a combination of classical genetic and molecular approaches. Mechanisms of organ-specific gene expression are a subject of intense research interest, as it is the operation of these mechanisms during eukaryotic development which determine the characteristics of each organism Allele-specific expression has been characterized in only a few other plant genes. In maize, organ-specific pigmentation regulated by the R, B, and Pl genes is achieved by differential transcription of functionally conserved protein coding sequences. Our studies point to a strikingly different mechanism of organ-specific gene expression, involving post-transcriptional regulation of the regulatory P gene. The novel pigmentation pattern of the P-wr allele is associated with differences in the encoded protein. Furthermore, the P-wr gene itself is present as a unique tandemly amplified structure, which may affect its transcriptional regulation.
The dek18 mutant of maize has decreased auxin content in kernels. Molecular and functional characterization of this mutant line offers the possibility to better understand auxin biology in maize seed development. Seeds of the dek18 mutants are smaller compared to wild type seeds and the vegetative d...
Although many insect resistance genes have been identified, the number of studies examining their effects in combination using transgenic systems is limited. We introduced a construct into maize containing the coding sequence for maize ribosome inactivating protein (MRIP), wheat germ agglutinin (WGA...
Akiyama, Hiroshi; Sakata, Kozue; Makiyma, Daiki; Nakamura, Kosuke; Teshima, Reiko; Nakashima, Akie; Ogawa, Asako; Yamagishi, Toru; Futo, Satoshi; Oguchi, Taichi; Mano, Junichi; Kitta, Kazumi
In many countries, the labeling of grains, feed, and foodstuff is mandatory if the genetically modified (GM) organism content exceeds a certain level of approved GM varieties. We previously developed an individual kernel detection system consisting of grinding individual kernels, DNA extraction from the individually ground kernels, GM detection using multiplex real-time PCR, and GM event detection using multiplex qualitative PCR to analyze the precise commingling level and varieties of GM maize in real sample grains. We performed the interlaboratory study of the DNA extraction with multiple ground samples, multiplex real-time PCR detection, and multiplex qualitative PCR detection to evaluate its applicability, practicality, and ruggedness for the individual kernel detection system of GM maize. DNA extraction with multiple ground samples, multiplex real-time PCR, and multiplex qualitative PCR were evaluated by five laboratories in Japan, and all results from these laboratories were consistent with the expected results in terms of the commingling level and event analysis. Thus, the DNA extraction with multiple ground samples, multiplex real-time PCR, and multiplex qualitative PCR for the individual kernel detection system is applicable and practicable in a laboratory to regulate the commingling level of GM maize grain for GM samples, including stacked GM maize.
Zeljenková, Dagmar; Aláčová, Radka; Ondrejková, Júlia; Ambrušová, Katarína; Bartušová, Mária; Kebis, Anton; Kovrižnych, Jevgenij; Rollerová, Eva; Szabová, Elena; Wimmerová, Soňa; Černák, Martin; Krivošíková, Zora; Kuricová, Miroslava; Líšková, Aurélia; Spustová, Viera; Tulinská, Jana; Levkut, Mikuláš; Révajová, Viera; Ševčíková, Zuzana; Schmidt, Kerstin; Schmidtke, Jörg; Schmidt, Paul; La Paz, Jose Luis; Corujo, Maria; Pla, Maria; Kleter, Gijs A; Kok, Esther J; Sharbati, Jutta; Bohmer, Marc; Bohmer, Nils; Einspanier, Ralf; Adel-Patient, Karine; Spök, Armin; Pöting, Annette; Kohl, Christian; Wilhelm, Ralf; Schiemann, Joachim; Steinberg, Pablo
The GRACE (GMO Risk Assessment and Communication of Evidence; www.grace-fp7.eu ) project was funded by the European Commission within the 7th Framework Programme. A key objective of GRACE was to conduct 90-day animal feeding trials, animal studies with an extended time frame as well as analytical, in vitro and in silico studies on genetically modified (GM) maize in order to comparatively evaluate their use in GM plant risk assessment. In the present study, the results of a 1-year feeding trial with a GM maize MON810 variety, its near-isogenic non-GM comparator and an additional conventional maize variety are presented. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 452. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after a chronic exposure.
Shi, Jinrui; Habben, Jeffrey E.; Archibald, Rayeann L.; Drummond, Bruce J.; Chamberlin, Mark A.; Williams, Robert W.; Lafitte, H. Renee; Weers, Ben P.
Lack of sufficient water is a major limiting factor to crop production worldwide, and the development of drought-tolerant germplasm is needed to improve crop productivity. The phytohormone ethylene modulates plant growth and development as well as plant response to abiotic stress. Recent research has shown that modifying ethylene biosynthesis and signaling can enhance plant drought tolerance. Here, we report novel negative regulators of ethylene signal transduction in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). These regulators are encoded by the ARGOS gene family. In Arabidopsis, overexpression of maize ARGOS1 (ZmARGOS1), ZmARGOS8, Arabidopsis ARGOS homolog ORGAN SIZE RELATED1 (AtOSR1), and AtOSR2 reduced plant sensitivity to ethylene, leading to enhanced drought tolerance. RNA profiling and genetic analysis suggested that the ZmARGOS1 transgene acts between an ethylene receptor and CONSTITUTIVE TRIPLE RESPONSE1 in the ethylene signaling pathway, affecting ethylene perception or the early stages of ethylene signaling. Overexpressed ZmARGOS1 is localized to the endoplasmic reticulum and Golgi membrane, where the ethylene receptors and the ethylene signaling protein ETHYLENE-INSENSITIVE2 and REVERSION-TO-ETHYLENE SENSITIVITY1 reside. In transgenic maize plants, overexpression of ARGOS genes also reduces ethylene sensitivity. Moreover, field testing showed that UBIQUITIN1:ZmARGOS8 maize events had a greater grain yield than nontransgenic controls under both drought stress and well-watered conditions. PMID:26220950
Zeljenková, Dagmar; Ambrušová, Katarína; Bartušová, Mária; Kebis, Anton; Kovrižnych, Jevgenij; Krivošíková, Zora; Kuricová, Miroslava; Líšková, Aurélia; Rollerová, Eva; Spustová, Viera; Szabová, Elena; Tulinská, Jana; Wimmerová, Soňa; Levkut, Mikuláš; Révajová, Viera; Ševčíková, Zuzana; Schmidt, Kerstin; Schmidtke, Jörg; La Paz, Jose Luis; Corujo, Maria; Pla, Maria; Kleter, Gijs A; Kok, Esther J; Sharbati, Jutta; Hanisch, Carlos; Einspanier, Ralf; Adel-Patient, Karine; Wal, Jean-Michel; Spök, Armin; Pöting, Annette; Kohl, Christian; Wilhelm, Ralf; Schiemann, Joachim; Steinberg, Pablo
The GMO Risk Assessment and Communication of Evidence (GRACE; www.grace-fp7.eu ) project is funded by the European Commission within the 7th Framework Programme. A key objective of GRACE is to conduct 90-day animal feeding trials, animal studies with an extended time frame as well as analytical, in vitro and in silico studies on genetically modified (GM) maize in order to comparatively evaluate their use in GM plant risk assessment. In the present study, the results of two 90-day feeding trials with two different GM maize MON810 varieties, their near-isogenic non-GM varieties and four additional conventional maize varieties are presented. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 408. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after subchronic exposure, independently of the two different genetic backgrounds of the event.
Chaikam, Vijay; Negeri, Adisu; Dhawan, Rahul; Puchaka, Bala; Ji, Jiabing; Chintamanani, Satya; Gachomo, Emma W; Zillmer, Allen; Doran, Timothy; Weil, Cliff; Balint-Kurti, Peter; Johal, Guri
The partially dominant, autoactive maize disease resistance gene Rp1-D21 causes hypersensitive response (HR) lesions to form spontaneously on leaves and stems in the absence of pathogen recognition. The maize nested association mapping (NAM) population consists of 25 200-line subpopulations each derived from a cross between the maize line B73 and one of 25 diverse inbred lines. By crossing a line carrying the Rp1-D21 gene with lines from three of these subpopulations and assessing the F(1) progeny, we were able to map several novel loci that modify the maize HR, using both single-population quantitative trait locus (QTL) and joint analysis of all three populations. Joint analysis detected QTL in greater number and with greater confidence and precision than did single population analysis. In particular, QTL were detected in bins 1.02, 4.04, 9.03, and 10.03. We have previously termed this technique, in which a mutant phenotype is used as a "reporter" for a trait of interest, Mutant-Assisted Gene Identification and Characterization (MAGIC).
He, Junguang; Dong, Zhigang; Jia, Zhiwei; Wang, Jianhua; Wang, Guoying
RNA-dependent RNA polymerases (RdRPs) in plants have been reported to be involved in post-transcriptional gene silencing (PTGS) and antiviral defense. In this report, an RdRP gene from maize (ZmRdRP1) was obtained by rapid amplification of cDNA ends (RACE) and RT-PCR. The mRNA of ZmRdRP1 was composed of 3785 nucleotides, including a 167 nt 5' untranslated region (UTR), a 291 nt 3'UTR and a 3327 nt open reading frame (ORF), which encodes a putative protein of 1108 amino acids with an estimated molecular mass of 126.9 kDa and a predicated isoelectric point (pI) of 8.37. Real-time quantitative RT-PCR analysis showed that ZmRdRP1 was elicited by salicylic acid (SA) treatment, methyl jasmonate (MeJA) treatment and sugarcane mosaic virus (SCMV) infection. We silenced ZmRdRP1 by constitutively expressing an inverted-repeat fragment of ZmRdRP1 (ir-RdRP1) in transgenic maize plants. Further studies revealed that the ir-RdRP1 transgenic plants were more susceptible to SCMV infection than wild type plants. Virus-infected transgenic maize plants developed more serious disease symptoms and accumulated more virus than wild type plants. These findings suggested that ZmRdRP1 was involved in antiviral defense in maize.
Takabatake, Reona; Koiwa, Tomohiro; Kasahara, Masaki; Takashima, Kaori; Futo, Satoshi; Minegishi, Yasutaka; Akiyama, Hiroshi; Teshima, Reiko; Oguchi, Taichi; Mano, Junichi; Furui, Satoshi; Kitta, Kazumi
To reduce the cost and time required to routinely perform the genetically modified organism (GMO) test, we developed a duplex quantitative real-time PCR method for a screening analysis simultaneously targeting an event-specific segment for GA21 and Cauliflower Mosaic Virus 35S promoter (P35S) segment [Oguchi et al., J. Food Hyg. Soc. Japan, 50, 117-125 (2009)]. To confirm the validity of the method, an interlaboratory collaborative study was conducted. In the collaborative study, conversion factors (Cfs), which are required to calculate the GMO amount (%), were first determined for two real-time PCR instruments, the ABI PRISM 7900HT and the ABI PRISM 7500. A blind test was then conducted. The limit of quantitation for both GA21 and P35S was estimated to be 0.5% or less. The trueness and precision were evaluated as the bias and reproducibility of the relative standard deviation (RSD(R)). The determined bias and RSD(R) were each less than 25%. We believe the developed method would be useful for the practical screening analysis of GM maize.
Gonzalez García, Eric; Ressmann, Anna K; Gaertner, Peter; Zirbs, Ronald; Mach, Robert L; Krska, Rudolf; Bica, Katharina; Brunner, Kurt
To date, the extraction of genomic DNA is considered a bottleneck in the process of genetically modified organisms (GMOs) detection. Conventional DNA isolation methods are associated with long extraction times and multiple pipetting and centrifugation steps, which makes the entire procedure not only tedious and complicated but also prone to sample cross-contamination. In recent times, ionic liquids have emerged as innovative solvents for biomass processing, due to their outstanding properties for dissolution of biomass and biopolymers. In this study, a novel, easily applicable, and time-efficient method for the direct extraction of genomic DNA from biomass based on aqueous-ionic liquid solutions was developed. The straightforward protocol relies on extraction of maize in a 10 % solution of ionic liquids in aqueous phosphate buffer for 5 min at room temperature, followed by a denaturation step at 95 °C for 10 min and a simple filtration to remove residual biopolymers. A set of 22 ionic liquids was tested in a buffer system and 1-ethyl-3-methylimidazolium dimethylphosphate, as well as the environmentally benign choline formate, were identified as ideal candidates. With this strategy, the quality of the genomic DNA extracted was significantly improved and the extraction protocol was notably simplified compared with a well-established method.
Sharma, Rinku; Singh, Nidhi; Mohan, Sweta; Mittal, Swati; Mittal, Shikha; Mallikarjuna, Mallana Gowdra; Rao, Atmakuri Ramakrishna; Dash, Prasanta Kumar; Hossain, Firoz; Gupta, Hari Shanker
A genomewide transcriptome assay of two subtropical genotypes of maize was used to observe the expression of genes at seedling stage of drought stress. The number of genes expressed differentially was greater in HKI1532 (a drought tolerant genotype) than in PC3 (a drought sensitive genotype), indicating primary differences at the transcriptional level in stress tolerance. The global coexpression networks of the two genotypes differed significantly with respect to the number of modules and the coexpression pattern within the modules. A total of 174 drought-responsive genes were selected from HKI1532, and their coexpression network revealed key correlations between different adaptive pathways, each cluster of the network representing a specific biological function. Transcription factors related to ABA-dependent stomatal closure, signalling, and phosphoprotein cascades work in concert to compensate for reduced photosynthesis. Under stress, water balance was maintained by coexpression of the genes involved in osmotic adjustments and transporter proteins. Metabolism was maintained by the coexpression of genes involved in cell wall modification and protein and lipid metabolism. The interaction of genes involved in crucial biological functions during stress was identified and the results will be useful in targeting important gene interactions to understand drought tolerance in greater detail. PMID:28326315
Nadal, Anna; Coll, Anna; La Paz, Jose-Luis; Esteve, Teresa; Pla, Maria
We present a novel multiplex PCR assay for simultaneous detection of multiple transgenic events in maize. Initially, five PCR primers pairs specific to events Bt11, GA21, MON810, and NK603, and Zea mays L. (alcohol dehydrogenase) were included. The event specificity was based on amplification of transgene/plant genome flanking regions, i.e., the same targets as for validated real-time PCR assays. These short and similarly sized amplicons were selected to achieve high and similar amplification efficiency for all targets; however, its unambiguous identification was a technical challenge. We achieved a clear distinction by a novel CGE approach that combined the identification by size and color (CGE-SC). In one single step, all five targets were amplified and specifically labeled with three different fluorescent dyes. The assay was specific and displayed an LOD of 0.1% of each genetically modified organism (GMO). Therefore, it was adequate to fulfill legal thresholds established, e.g., in the European Union. Our CGE-SC based strategy in combination with an adequate labeling design has the potential to simultaneously detect higher numbers of targets. As an example, we present the detection of up to eight targets in a single run. Multiplex PCR-CGE-SC only requires a conventional sequencer device and enables automation and high throughput. In addition, it proved to be transferable to a different laboratory. The number of authorized GMO events is rapidly growing; and the acreage of genetically modified (GM) varieties cultivated and commercialized worldwide is rapidly increasing. In this context, our multiplex PCR-CGE-SC can be suitable for screening GM contents in food.
Yang, Litao; Xu, Songci; Pan, Aihu; Yin, Changsong; Zhang, Kewei; Wang, Zhenying; Zhou, Zhigang; Zhang, Dabing
Because of the genetically modified organisms (GMOs) labeling policies issued in many countries and areas, polymerase chain reaction (PCR) methods were developed for the execution of GMO labeling policies, such as screening, gene specific, construct specific, and event specific PCR detection methods, which have become a mainstay of GMOs detection. The event specific PCR detection method is the primary trend in GMOs detection because of its high specificity based on the flanking sequence of the exogenous integrant. This genetically modified maize, MON863, contains a Cry3Bb1 coding sequence that produces a protein with enhanced insecticidal activity against the coleopteran pest, corn rootworm. In this study, the 5'-integration junction sequence between the host plant DNA and the integrated gene construct of the genetically modified maize MON863 was revealed by means of thermal asymmetric interlaced-PCR, and the specific PCR primers and TaqMan probe were designed based upon the revealed 5'-integration junction sequence; the conventional qualitative PCR and quantitative TaqMan real-time PCR detection methods employing these primers and probes were successfully developed. In conventional qualitative PCR assay, the limit of detection (LOD) was 0.1% for MON863 in 100 ng of maize genomic DNA for one reaction. In the quantitative TaqMan real-time PCR assay, the LOD and the limit of quantification were eight and 80 haploid genome copies, respectively. In addition, three mixed maize samples with known MON863 contents were detected using the established real-time PCR systems, and the ideal results indicated that the established event specific real-time PCR detection systems were reliable, sensitive, and accurate.
Song, Qingxin; Juenger, Thomas E.
Heterosis has been widely used in agriculture, but the molecular mechanism for this remains largely elusive. In Arabidopsis hybrids and allopolyploids, increased photosynthetic and metabolic activities are linked to altered expression of circadian clock regulators, including CIRCADIAN CLOCK ASSOCIATED1 (CCA1). It is unknown whether a similar mechanism mediates heterosis in maize hybrids. Here we report that higher levels of carbon fixation and starch accumulation in the maize hybrids are associated with altered temporal gene expression. Two maize CCA1 homologs, ZmCCA1a and ZmCCA1b, are diurnally up-regulated in the hybrids. Expressing ZmCCA1 complements the cca1 mutant phenotype in Arabidopsis, and overexpressing ZmCCA1b disrupts circadian rhythms and biomass heterosis. Furthermore, overexpressing ZmCCA1b in maize reduced chlorophyll content and plant height. Reduced height stems from reduced node elongation but not total node number in both greenhouse and field conditions. Phenotypes are less severe in the field than in the greenhouse, suggesting that enhanced light and/or metabolic activities in the field can compensate for altered circadian regulation in growth vigor. Chromatin immunoprecipitation-sequencing (ChIP-seq) analysis reveals a temporal shift of ZmCCA1-binding targets to the early morning in the hybrids, suggesting that activation of morning-phased genes in the hybrids promotes photosynthesis and growth vigor. This temporal shift of ZmCCA1-binding targets correlated with nonadditive and additive gene expression in early and late stages of seedling development. These results could guide breeding better hybrid crops to meet the growing demand in food and bioenergy. PMID:27467757
Wang, Bo; Chen, Yanhong; Guo, Baojian; Kabir, Muhammad Rezaul; Yao, Yingyin; Peng, Huiru; Xie, Chaojie; Zhang, Yirong; Sun, Qixin; Ni, Zhongfu
Cytokinin signaling is vital for plant growth and development which function via the two-component system (TCS). As one of the key component of TCS, transmembrane histidine kinases (HK) are encoded by a small gene family in plants. In this study, we focused on expression and functional analysis of cytokinin receptor-like HK genes (ZmHK) in maize. Firstly, bioinformatics analysis revealed that seven cloned ZmHK genes have different expression patterns during maize development. Secondly, ectopic expression by CaMV35S promoter in Arabidopsis further revealed that functional differentiation exists among these seven members. Among them, the ZmHK1a2-OX transgenic line has the lowest germination rate in the dark, ZmHK1-OX and ZmHK2a2-OX can delay leaf senescence, and seed size of ZmHK1-OX, ZmHK1a2-OX, ZmHK2-OX, ZmHK3b-OX and ZmHK2a2-OX was obviously reduced as compared to wild type. Additionally, ZmHK genes play opposite roles in shoot and root development; all ZmHK-OX transgenic lines display obvious shorter root length and reduced number of lateral roots, but enhanced shoot development compared with the wild type. Most notably, Arabidopsis response regulator ARR5 gene was up-regulated in ZmHK1-OX, ZmHK1a2-OX, ZmHK2-OX, ZmHK3b-OX and ZmHK2a2-OX as compared to wild type. Although the causal link between ZmHK genes and cytokinin signaling pathway is still an area to be further elucidated, these findings reflected that the diversification of ZmHK genes expression patterns and functions occurred in the course of maize evolution, indicating that some ZmHK genes might play different roles during maize development.
Ko, Dae Kwan; Rohozinski, Dominica; Song, Qingxin; Taylor, Samuel H; Juenger, Thomas E; Harmon, Frank G; Chen, Z Jeffrey
Heterosis has been widely used in agriculture, but the molecular mechanism for this remains largely elusive. In Arabidopsis hybrids and allopolyploids, increased photosynthetic and metabolic activities are linked to altered expression of circadian clock regulators, including CIRCADIAN CLOCK ASSOCIATED1 (CCA1). It is unknown whether a similar mechanism mediates heterosis in maize hybrids. Here we report that higher levels of carbon fixation and starch accumulation in the maize hybrids are associated with altered temporal gene expression. Two maize CCA1 homologs, ZmCCA1a and ZmCCA1b, are diurnally up-regulated in the hybrids. Expressing ZmCCA1 complements the cca1 mutant phenotype in Arabidopsis, and overexpressing ZmCCA1b disrupts circadian rhythms and biomass heterosis. Furthermore, overexpressing ZmCCA1b in maize reduced chlorophyll content and plant height. Reduced height stems from reduced node elongation but not total node number in both greenhouse and field conditions. Phenotypes are less severe in the field than in the greenhouse, suggesting that enhanced light and/or metabolic activities in the field can compensate for altered circadian regulation in growth vigor. Chromatin immunoprecipitation-sequencing (ChIP-seq) analysis reveals a temporal shift of ZmCCA1-binding targets to the early morning in the hybrids, suggesting that activation of morning-phased genes in the hybrids promotes photosynthesis and growth vigor. This temporal shift of ZmCCA1-binding targets correlated with nonadditive and additive gene expression in early and late stages of seedling development. These results could guide breeding better hybrid crops to meet the growing demand in food and bioenergy.
Liu, Fushan; Ahmed, Zaheer; Lee, Elizabeth A.; Donner, Elizabeth; Liu, Qiang; Ahmed, Regina; Morell, Matthew K.; Emes, Michael J.; Tetlow, Ian J.
amylose extender (ae−) starches characteristically have modified starch granule morphology resulting from amylopectin with reduced branch frequency and longer glucan chains in clusters, caused by the loss of activity of the major starch branching enzyme (SBE), which in maize endosperm is SBEIIb. A recent study with ae− maize lacking the SBEIIb protein (termed ae1.1 herein) showed that novel protein–protein interactions between enzymes of starch biosynthesis in the amyloplast could explain the starch phenotype of the ae1.1 mutant. The present study examined an allelic variant of the ae− mutation, ae1.2, which expresses a catalytically inactive form of SBEIIb. The catalytically inactive SBEIIb in ae1.2 lacks a 28 amino acid peptide (Val272–Pro299) and is unable to bind to amylopectin. Analysis of starch from ae1.2 revealed altered granule morphology and physicochemical characteristics distinct from those of the ae1.1 mutant as well as the wild-type, including altered apparent amylose content and gelatinization properties. Starch from ae1.2 had fewer intermediate length glucan chains (degree of polymerization 16–20) than ae1.1. Biochemical analysis of ae1.2 showed that there were differences in the organization and assembly of protein complexes of starch biosynthetic enzymes in comparison with ae1.1 (and wild-type) amyloplasts, which were also reflected in the composition of starch granule-bound proteins. The formation of stromal protein complexes in the wild-type and ae1.2 was strongly enhanced by ATP, and broken by phosphatase treatment, indicating a role for protein phosphorylation in their assembly. Labelling experiments with [γ-32P]ATP showed that the inactive form of SBEIIb in ae1.2 was phosphorylated, both in the monomeric form and in association with starch synthase isoforms. Although the inactive SBEIIb was unable to bind starch directly, it was strongly associated with the starch granule, reinforcing the conclusion that its presence in the
Hayano-Kanashiro, Corina; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis; Simpson, June
Background Drought is one of the major constraints for plant productivity worldwide. Different mechanisms of drought-tolerance have been reported for several plant species including maize. However, the differences in global gene expression between drought-tolerant and susceptible genotypes and their relationship to physiological adaptations to drought are largely unknown. The study of the differences in global gene expression between tolerant and susceptible genotypes could provide important information to design more efficient breeding programs to produce maize varieties better adapted to water limiting conditions. Methodology/Principal Findings Changes in physiological responses and gene expression patterns were studied under drought stress and recovery in three Mexican maize landraces which included two drought tolerant (Cajete criollo and Michoacán 21) and one susceptible (85-2) genotypes. Photosynthesis, stomatal conductance, soil and leaf water potentials were monitored throughout the experiment and microarray analysis was carried out on transcripts obtained at 10 and 17 days following application of stress and after recovery irrigation. The two tolerant genotypes show more drastic changes in global gene expression which correlate with different physiological mechanisms of adaptation to drought. Differences in the kinetics and number of up- and down-regulated genes were observed between the tolerant and susceptible maize genotypes, as well as differences between the two tolerant genotypes. Interestingly, the most dramatic differences between the tolerant and susceptible genotypes were observed during recovery irrigation, suggesting that the tolerant genotypes activate mechanisms that allow more efficient recovery after a severe drought. Conclusions/Significance A correlation between levels of photosynthesis and transcription under stress was observed and differences in the number, type and expression levels of transcription factor families were also
Background The Maternally expressed gene (Meg) family is a locally-duplicated gene family of maize which encodes cysteine-rich proteins (CRPs). The founding member of the family, Meg1, is required for normal development of the basal endosperm transfer cell layer (BETL) and is involved in the allocation of maternal nutrients to growing seeds. Despite the important roles of Meg1 in maize seed development, the evolutionary history of the Meg cluster and the activities of the duplicate genes are not understood. Results In maize, the Meg gene cluster resides in a 2.3 Mb-long genomic region that exhibits many features of non-centromeric heterochromatin. Using phylogenetic reconstruction and syntenic alignments, we identified the pedigree of the Meg family, in which 11 of its 13 members arose in maize after allotetraploidization ~4.8 mya. Phylogenetic and population-genetic analyses identified possible signatures suggesting recent positive selection in Meg homologs. Structural analyses of the Meg proteins indicated potentially adaptive changes in secondary structure from α-helix to β-strand during the expansion. Transcriptomic analysis of the maize endosperm indicated that 6 Meg genes are selectively activated in the BETL, and younger Meg genes are more active than older ones. In endosperms from B73 by Mo17 reciprocal crosses, most Meg genes did not display parent-specific expression patterns. Conclusions Recently-duplicated Meg genes have different protein secondary structures, and their expressions in the BETL dominate over those of older members. Together with the signs of positive selections in the young Meg genes, these results suggest that the expansion of the Meg family involves potentially adaptive transitions in which new members with novel functions prevailed over older members. PMID:25084677
Impact of genetic structures on haploid genome-based quantification of genetically modified DNA: theoretical considerations, experimental data in MON 810 maize kernels (Zea mays L.) and some practical applications.
Zhang, David; Corlet, Aurélie; Fouilloux, Stephane
Real-time Polymerase Chain Reaction (PCR) based assays are widely used to estimate the content of genetically modified (GM) materials in food, feed and seed. It has been known that the genetic structures of the analyte can significantly influence the GM content expressed by the haploid genome (HG) % estimated using real-time PCR assays; this kind of influence is also understood as the impact of biological factors. The influence was first simulated at theoretical level using maize as a model. We then experimentally assessed the impact of biological factors on quantitative results, analysing by quantitative real-time PCR six maize MON 810 hybrid kernels with different genetic structures: (1) hemizygous from transgenic male parent, (2) hemizygous from transgenic female parent and (3) homozygous at the transgenic locus. The results obtained in the present study showed clear influences of biological factors on GM DNA quantification: 1% of GM materials by weight (wt) for the three genetic structures contained 0.39, 0.55 and 1.0% of GM DNA by HG respectively, from quantitative real-time PCR analyses. The relationships between GM wt% and GM HG% can be empirically established as: (1) in the case of the presence of a single GM trait: GM HG% = GM wt% x (0.5 +/- 0.167Y), where Y is the endosperm DNA content (%) in the total DNA of a maize kernel, (2) in the case of the presence of multiple GM traits: GM HG% = N x GM wt% x (0.5 +/- 0.167Y), where N is the number of GM traits (stacked or not) present in an unknown sample. This finding can be used by stakeholders related to GMO for empirical prediction from one unit of expression to another in the monitoring of seed and grain production chains. Practical equations have also been suggested for haploid copy number calculations, using hemizygous GM materials for calibration curves.
Chen, Wei; Zhu, Qilin; Wang, Haiyan; Xiao, Jin; Xing, Liping; Chen, Peidu; Jin, Weiwei; Wang, Xiu-E
Uniparental chromosome elimination in wheat × maize hybrid embryos is widely used in double haploid production of wheat. Several explanations have been proposed for this phenomenon, one of which is that the lack of cross-species CENH3 incorporation may act as a barrier to interspecies hybridization. However, it is unknown if this mechanism applies universally. To study the role of CENH3 in maize chromosome elimination of wheat × maize hybrid embryos, maize ZmCENH3 and wheat αTaCENH3-B driven by the constitutive CaMV35S promoter were transformed into wheat variety Yangmai 158. Five transgenic lines for ZmCENH3 and six transgenic lines for αTaCENH3-B were identified. RT-PCR analysis showed that the transgene could be transcribed at a low level in all ZmCENH3 transgenic lines, whereas transcription of endogenous wheat CENH3 was significantly up-regulated. Interestingly, the expression levels of both wheat CENH3 and ZmCENH3 in the ZmCENH3 transgenic wheat × maize hybrid embryos were higher than those in the non-transformed Yangmai 158 × maize hybrid embryos. This indicates that the alien ZmCENH3 in wheat may induce competitive expression of endogenous wheat CENH3, leading to suppression of ZmCENH3 over-expression. Eliminations of maize chromosomes in hybrid embryos of ZmCENH3 transgenic wheat × maize and Yangmai 158 × maize were compared by observations on micronuclei presence, by marker analysis using maize SSRs (simple sequence repeats), and by FISH (fluorescence in situ hybridization) using 45S rDNA as a probe. The results indicate that maize chromosome elimination events in the two crosses are not significantly different. Fusion protein ZmCENH3-YFP could not be detected in ZmCENH3 transgenic wheat by either Western blotting or immnunostaining, whereas accumulation and loading of the αTaCENH3-B-GFP fusion protein was normal in αTaCENH3-B transgenic lines. As ZmCENH3-YFP did not accumulate after AM114 treatment, we speculate that low levels of Zm
Böhme, H; Aulrich, K; Daenicke, R; Flachowsky, G
To analyse substantial equivalence of genetically modified sugar-beets and maize, in which the glufosinate-tolerant (Pat) gene is inserted, crude nutrients, the amino acid and the fatty acid profiles as well as the composition of the NDF-fraction of maize grains were determined and compared with those of the corresponding non-transgenic cultivars. Due to the genetic manipulation differences in crude nutrient contents including sugar and starch were not detected. The amino acid profile of maize grains was analysed to be the same. Fatty acid profile and composition of cell wall constituents did not show any influences as well. Digestibility of Pat-sugar-beets and maize grains for pigs did not demonstrate meaningful differences as compared to the corresponding non-transgenic cultivars. Digestibility of sugar-beet roots and sugar-beet top silage for ruminants proved to be also in the scope of natural variance. As the digestibility of the macro nutrients remained unaffected, the Pat-gene introduction into both crops did not show an influence on the energetic feeding value. For pigs the ME-content of Pat-sugar-beets was determined to be 14.1 MJ/kg DM versus 13.7 MJ of the non-transgenic cultivars. ME-content of Pat-maize grains was 16.0 MJ/kg DM versus 15.8 MJ for controls. For ruminants the feeding value of Pat-sugar-beets was found to be 8.5 MJ NEL/kg DM or 13.2 MJ ME/kg DM, regardless of whether the Pat-gene was inserted or not. The corresponding energy values of sugar-beet top silage ranged between 5.2 and 5.5 MJ NEL/kg DM or 8.6 and 9.1 MJ ME/kg DM, with differences considered in the biological range.
Takabatake, Reona; Masubuchi, Tomoko; Futo, Satoshi; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Teshima, Reiko; Kurashima, Takeyo; Mano, Junichi; Kitta, Kazumi
A novel real-time PCR-based analytical method was developed for the event-specific quantification of a genetically modified (GM) maize, 3272. We first attempted to obtain genome DNA from this maize using a DNeasy Plant Maxi kit and a DNeasy Plant Mini kit, which have been widely utilized in our previous studies, but DNA extraction yields from 3272 were markedly lower than those from non-GM maize seeds. However, lowering of DNA extraction yields was not observed with GM quicker or Genomic-tip 20/G. We chose GM quicker for evaluation of the quantitative method. We prepared a standard plasmid for 3272 quantification. The conversion factor (Cf), which is required to calculate the amount of a genetically modified organism (GMO), was experimentally determined for two real-time PCR instruments, the Applied Biosystems 7900HT (the ABI 7900) and the Applied Biosystems 7500 (the ABI7500). The determined Cf values were 0.60 and 0.59 for the ABI 7900 and the ABI 7500, respectively. To evaluate the developed method, a blind test was conducted as part of an interlaboratory study. The trueness and precision were evaluated as the bias and reproducibility of the relative standard deviation (RSDr). The determined values were similar to those in our previous validation studies. The limit of quantitation for the method was estimated to be 0.5% or less, and we concluded that the developed method would be suitable and practical for detection and quantification of 3272.
Paulis, J W; Bietz, J A; Bogyo, T P; Nelsen, T C; Darrah, L L; Zuber, M S
Zeins, the major endosperm proteins in maize (Zea mays L.), are deficient in the essential amino acids lysine and tryptophan. Some mutant genes, like opaque-2 (o2) and floury-2 (fl2), reduce the levels of A- and B-zeins, thereby improving maize's nutritional value. Other mutants, such as amylose-extender (ae), floury-1 (fl1), soft starch (h), dull-1 (du), shrunken-1 (sh1), sugary-1 (su1), sugary-2 (su2), and waxy (wx), primarily affect starch composition, but also alter zein composition. We undertook this study to examine the effects of some of these mutant genes on A/B-zein composition and to study the interactions of these genes in double-mutant combinations. Endosperm prolamins were extracted from inbred B37, ten near-isogenic single mutants (ae, du, fl1, fl2, h, o2, sh1, su1, su2, and wx), and most double-mutant combinations. Zeins in these extracts were fractionated by reversed-phase highperformance liquid chromatography (RP-HPLC) into 22-24 peaks. Of the resulting 22 major peaks the areas of 16 (per milligram endosperm) were significantly affected by individual mutant genes relative to the zein composition of the normal inbred. In combination these genes exhibited significant epistatic interactions in regulating the expression of individual A/B zeins. Epistatic interactions were judged to be significant when the amount of a peak in a double mutant differed from the averages for the peak in the two respective single mutants. The o2 gene, alone and in combination with other mutant genes, significantly decreased the amounts of many individual zeins. The effect of the o2 gene was the greatest of all the genes examined. Various clustering techniques were used to see if mutant effects could be grouped; among these was principal component analysis, a multivariate statistical technique that analyzes all peak sizes simultaneously. Three-dimensional scatter graphs were constructed based on the first three principal components. For the single mutants, these showed no
Constantino, Nasie N; Mastouri, Fatemeh; Damarwinasis, Ramadhika; Borrego, Eli J; Moran-Diez, Maria E; Kenerley, Charley M; Gao, Xiquan; Kolomiets, Michael V
We have previously reported that disruption of a maize root-expressed 9-lipoxygenase (9-LOX) gene, ZmLOX3, results in dramatic increase in resistance to diverse leaf and stalk pathogens. Despite evident economic significance of these findings, the mechanism behind this increased resistance remained elusive. In this study, we found that increased resistance of the lox3-4 mutants is due to constitutive activation of induced systemic resistance (ISR) signaling. We showed that ZmLOX3 lacked expression in leaves in response to anthracnose leaf blight pathogen Colletotrichum graminicola, but was expressed constitutively in the roots, thus, prompting our hypothesis: the roots of lox3-4 mutants are the source of increased resistance in leaves. Supporting this hypothesis, treatment of wild-type plants (WT) with xylem sap of lox3-4 mutant induced resistance to C. graminicola to the levels comparable to those observed in lox3-4 mutant. Moreover, treating mutants with the sap collected from WT plants partially restored the susceptibility to C. graminicola. lox3-4 mutants showed primed defense responses upon infection, which included earlier and greater induction of defense-related PAL and GST genes compared to WT. In addition to the greater expression of the octadecanoid pathway genes, lox3-4 mutant responded earlier and with a greater accumulation of H2O2 in response to C. graminicola infection or treatment with alamethicin. These findings suggest that lox3-4 mutants display constitutive ISR-like signaling. In support of this idea, root colonization by Trichoderma virens strain GV29-8 induced the same level of disease resistance in WT as the treatment with the mutant sap, but had no additional resistance effect in lox3-4 mutant. While treatment with T. virens GV29 strongly and rapidly suppressed ZmLOX3 expression in hydroponically grown WT roots, T. virens Δsml mutant, which is deficient in ISR induction, was unable to suppress expression of ZmLOX3, thus, providing genetic
Osman, Gamal H; Assem, Shireen K; Alreedy, Rasha M; El-Ghareeb, Doaa K; Basry, Mahmoud A; Rastogi, Anshu; Kalaji, Hazem M
Due to the importance of chitinolytic enzymes for insect, nematode and fungal growth, they are receiving attention concerning their development as biopesticides or chemical defense proteins in transgenic plants and as microbial biocontrol agents. Targeting chitin associated with the extracellular matrices or cell wall by insect chitinases may be an effective approach for controlling pest insects and pathogenic fungi. The ability of chitinases to attack and digest chitin in the peritrophic matrix or exoskeleton raises the possibility to use them as insect control method. In this study, an insect chitinase cDNA from cotton leaf worm (Spodoptera littoralis) has been synthesized. Transgenic maize plant system was used to improve its tolerance against insects. Insect chitinase transcripts and proteins were expressed in transgenic maize plants. The functional integrity and expression of chitinase in progenies of the transgenic plants were confirmed by insect bioassays. The bioassays using transgenic corn plants against corn borer (Sesamia cretica) revealed that ~50% of the insects reared on transgenic corn plants died, suggesting that transgenic maize plants have enhanced resistance against S. cretica.
Moore, R E; Davies, M S; O'Connell, K M; Harding, E I; Wiegand, R C; Tiemeier, D C
The isolation and characterization of a family of maize glutathione-S-transferases (GST's) has been described previously. These enzymes are designated GSTs I, II and III based on size, substrate specificity and responsiveness to safeners. GST III has been shown to act on the herbicide alachlor as well as the commonly used substrate 1-chloro-2,4-dinitrobenzene (CDNB). Clones were isolated from a maize cDNA library in lambda gt10. Three clones contained the entire coding region for GST III. The sequences of these clones were consistent with the known amino terminal GST III protein sequence. Moreover, expression of one of these clones in E. coli resulted in a GST activity as measured with both CDNB and alachlor, proving that at least one of the clones encodes an active GST III species. With the enzyme expressed in E. coli it will become possible to study enzyme structure-function relationships ex planta. While a number of different GST proteins are present in maize tissue the GST III gene is present in single or low copy in the genome.
Moore, R E; Davies, M S; O'Connell, K M; Harding, E I; Wiegand, R C; Tiemeier, D C
The isolation and characterization of a family of maize glutathione-S-transferases (GST's) has been described previously. These enzymes are designated GSTs I, II and III based on size, substrate specificity and responsiveness to safeners. GST III has been shown to act on the herbicide alachlor as well as the commonly used substrate 1-chloro-2,4-dinitrobenzene (CDNB). Clones were isolated from a maize cDNA library in lambda gt10. Three clones contained the entire coding region for GST III. The sequences of these clones were consistent with the known amino terminal GST III protein sequence. Moreover, expression of one of these clones in E. coli resulted in a GST activity as measured with both CDNB and alachlor, proving that at least one of the clones encodes an active GST III species. With the enzyme expressed in E. coli it will become possible to study enzyme structure-function relationships ex planta. While a number of different GST proteins are present in maize tissue the GST III gene is present in single or low copy in the genome. Images PMID:3532034
Osman, Gamal H.; Assem, Shireen K.; Alreedy, Rasha M.; El-Ghareeb, Doaa K.; Basry, Mahmoud A.; Rastogi, Anshu; Kalaji, Hazem M.
Due to the importance of chitinolytic enzymes for insect, nematode and fungal growth, they are receiving attention concerning their development as biopesticides or chemical defense proteins in transgenic plants and as microbial biocontrol agents. Targeting chitin associated with the extracellular matrices or cell wall by insect chitinases may be an effective approach for controlling pest insects and pathogenic fungi. The ability of chitinases to attack and digest chitin in the peritrophic matrix or exoskeleton raises the possibility to use them as insect control method. In this study, an insect chitinase cDNA from cotton leaf worm (Spodoptera littoralis) has been synthesized. Transgenic maize plant system was used to improve its tolerance against insects. Insect chitinase transcripts and proteins were expressed in transgenic maize plants. The functional integrity and expression of chitinase in progenies of the transgenic plants were confirmed by insect bioassays. The bioassays using transgenic corn plants against corn borer (Sesamia cretica) revealed that ~50% of the insects reared on transgenic corn plants died, suggesting that transgenic maize plants have enhanced resistance against S. cretica. PMID:26658494
Forestan, Cristian; Aiese Cigliano, Riccardo; Farinati, Silvia; Lunardon, Alice; Sanseverino, Walter; Varotto, Serena
Plant’s response and adaptation to abiotic stresses involve sophisticated genetic and epigenetic regulatory systems. To obtain a global view of molecular response to osmotic stresses, including the non-coding portion of genome, we conducted a total leaf transcriptome analysis on maize plants subjected to prolonged drought and salt stresses. Stress application to both B73 wild type and the epiregulator mutant rpd1-1/rmr6 allowed dissection of the epigenetic component of stress response. Coupling total RNA-Seq and transcriptome re-assembly we annotated thousands of new maize transcripts, together with 13,387 lncRNAs that may play critical roles in regulating gene expression. Differential expression analysis revealed hundreds of genes modulated by long-term stress application, including also many lncRNAs and transposons specifically induced by stresses. The amplitude and dynamic of the stress-modulated gene sets are very different between B73 and rpd1-1/rmr6 mutant plants, as result of stress-like effect on genome regulation caused by the mutation itself, which activates many stress-related genes even in control condition. The analyzed extensive set of total RNA-Seq data, together with the improvement of the transcriptome and the identification of the non-coding portion of the transcriptome give a revealing insight into the genetic and epigenetic mechanism responsible for maize molecular response to abiotic stresses. PMID:27461139
Kelliher, Timothy; Walbot, Virginia
In flowering plants, anthers are the site of de novo germinal cell specification, male meiosis, and pollen development. Atypically, anthers lack a meristem. Instead, both germinal and somatic cell types differentiate from floral stem cells packed into anther lobes. To better understand anther cell fate specification and to provide a resource for the reproductive biology community, we isolated cohorts of germinal and somatic initials from maize anthers within 36 h of fate acquisition, identifying 815 specific and 1714 significantly enriched germinal transcripts, plus 2439 specific and 2112 significantly enriched somatic transcripts. To clarify transcripts involved in cell differentiation, we contrasted these profiles to anther primordia prior to fate specification and to msca1 anthers arrested in the first step of fate specification and hence lacking normal cell types. The refined cell-specific profiles demonstrated that both germinal and somatic cell populations differentiate quickly and express unique transcription factor sets; a subset of transcript localizations was validated by in situ hybridization. Surprisingly, germinal initials starting 5 days of mitotic divisions were enriched significantly in >100 transcripts classified in meiotic processes that included recombination and synapsis, along with gene sets involved in RNA metabolism, redox homeostasis, and cytoplasmic ATP generation. Enrichment of meiotic-specific genes in germinal initials challenges current dogma that the mitotic to meiotic transition occurs later in development during pre-meiotic S phase. Expression of cytoplasmic energy generation genes suggests that male germinal cells accommodate hypoxia by diverting carbon away from mitochondrial respiration into alternative pathways that avoid producing reactive oxygen species (ROS).
Rao, Jun; Yang, Litao; Wang, Congmao; Zhang, Dabing; Shi, Jianxin
The next generation sequencing technologies have been recently used for transcriptome analysis in many organisms because of the decreased sequencing cost and increased sequence output. In this study, we used digital gene expression (DGE) technique to compare the transcriptomic changes in mature seeds between transgenic maize overexpressing Aspergillus niger phyA2 and its non-transgenic counterpart. Deep sequencing of DGE libraries of the transgenic and its non-transgenic counterpart seeds generated 3,783,500 and 3,790,500 reads of 21-nucleotide, respectively, with frequencies spanning over four orders of magnitude. In transgenic maize, 53.97% of the unambiguous signature tags were mapped to the maize B73 reference genome, and 46.47% of genes were detected by at least two reads; in non-transgenic maize, the corresponding numbers were 51.38% and 47.39%. Compared with non-transgenic counterpart, about 12% of detected genes were differentially expressed in the transcriptome of transgenic maize seeds. Among these differentially expressed genes, there were 23 transcription factors in 14 families and no allergen genes. Pathway enrichment analysis revealed that 21 pathways were significantly affected by the transgenic event, in which the pathway involved in protein processing in endoplasmic reticulum was the most significantly affected. Results from this study indicated that both intended and unintended transcriptomic changes occurred in the transgenic maize, thus emphasizing the importance of transcriptome profiling in risk assessment of transgenic events.
Feng, Shangguo; Yue, Runqing; Tao, Sun; Yang, Yanjun; Zhang, Lei; Xu, Mingfeng; Wang, Huizhong; Shen, Chenjia
Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes participate in auxin homeostasis by catalyzing auxin conjugation and bounding free indole-3-acetic acid (IAA) to amino acids. However, how GH3 genes function in responses to abiotic stresses and various hormones in maize is largely unknown. Here, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmGH3 family genes from maize. The results showed that 13 ZmGH3 genes were mapped on five maize chromosomes (total 10 chromosomes). Highly diversified gene structures and tissue-specific expression patterns suggested the possibility of function diversification for these genes in response to environmental stresses and hormone stimuli. The expression patterns of ZmGH3 genes are responsive to several abiotic stresses (salt, drought and cadmium) and major stress-related hormones (abscisic acid, salicylic acid and jasmonic acid). Various environmental factors suppress auxin free IAA contents in maize roots suggesting that these abiotic stresses and hormones might alter GH3-mediated auxin levels. The responsiveness of ZmGH3 genes to a wide range of abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses.
Sui, Zhenhua; Niu, Linyuan; Yue, Guidong; Yang, Aifang; Zhang, Juren
Previous studies have indicated the phosphoinositide and phospholipid signaling pathways play a key role in plant growth, development and responses to environmental stresses. However, little is known about the phosphoinositide and phospholipid signaling pathways in maize (Zea mays L.). To better understand the function of genes involved in the phosphoinositide and phospholipid signaling pathways in maize, the cDNA sequences of ZmPIS2, ZmPLC2, ZmDGK1, ZmDGK2 and ZmDGK3 were obtained by RACE (rapid amplification of cDNA ends) or in silico cloning combined with PCR. RT-PCR analysis of cDNA from five tissues (roots, stems, leaves, tassels, and ears) indicated that the expression patterns of the five cDNAs we isolated as well as ZmPIS, ZmPLC, ZmPLD varied in different tissues. To determine the effects of different environmental conditions such as cold, drought and various phytohormones (abscisic acid, indole-3-acetic acid and gibberellic acid) on gene expression, we analyzed expression by Real-Time (RT-PCR), and found that the different isoforms of these gene families involved in the phosphoinositide and phospholipid signaling pathways have specific expression patterns. Our results suggested that these genes may be involved in the responses to environmental stresses, but have different functions. The isolation and analysis of expression patterns of genes involved in the phosphoinositide and phospholipid signaling pathways provides a good basis for further research of the phosphoinositide and phospholipid signaling pathways in maize and is a novel supplement to our comprehension of these pathways in plants.
Noguchi, Akio; Nakamura, Kosuke; Sakata, Kozue; Sato-Fukuda, Nozomi; Ishigaki, Takumi; Mano, Junichi; Takabatake, Reona; Kitta, Kazumi; Teshima, Reiko; Kondo, Kazunari; Nishimaki-Mogami, Tomoko
A number of genetically modified (GM) maize events have been developed and approved worldwide for commercial cultivation. A screening method is needed to monitor GM maize approved for commercialization in countries that mandate the labeling of foods containing a specified threshold level of GM crops. In Japan, a screening method has been implemented to monitor approved GM maize since 2001. However, the screening method currently used in Japan is time-consuming and requires generation of a calibration curve and experimental conversion factor (C(f)) value. We developed a simple screening method that avoids the need for a calibration curve and C(f) value. In this method, ΔC(q) values between the target sequences and the endogenous gene are calculated using multiplex real-time PCR, and the ΔΔC(q) value between the analytical and control samples is used as the criterion for determining analytical samples in which the GM organism content is below the threshold level for labeling of GM crops. An interlaboratory study indicated that the method is applicable independently with at least two models of PCR instruments used in this study.
Schmidt, Kerstin; Schmidtke, Jörg; Schmidt, Paul; Kohl, Christian; Wilhelm, Ralf; Schiemann, Joachim; van der Voet, Hilko; Steinberg, Pablo
The data of four 90-day feeding trials and a 1-year feeding trial with the genetically modified (GM) maize MON810 in Wistar Han RCC rats performed in the frame of EU-funded project GRACE were analysed. Firstly, the data obtained from the groups having been fed the non-GM maize diets were combined to establish a historical control data set for Wistar Han RCC rats at the animal housing facility (Slovak Medical University, Bratislava, Slovakia). The variability of all parameters is described, and the reference values and ranges have been derived. Secondly, the consistency of statistically significant differences found in the five studies was analysed. In order to do so, the body weight development, organ weight, haematology and clinical biochemistry data were compared between the studies. Based on the historical control data, equivalence ranges for these parameters were defined, and the values measured in the GM maize-fed groups were compared with these equivalence ranges. Thirdly, the (statistical) power of these feeding studies with whole food/feed was assessed and detectable toxicologically relevant group differences were derived. Linear mixed models (LMM) were applied, and standardized effect sizes (SES) were calculated in order to compare different parameters as well as to provide an overall picture of group and study differences at a glance. The comparison of the five feeding trials showed a clear study effect in the control data. It also showed inconsistency both in the frequency of statistically significant differences and in the difference values between control and test groups.
Koc, Anna; Cañuelo, Ana; Garcia-Reyes, Juan F; Molina-Diaz, Antonio; Trojanowicz, Marek
In this work, the use of liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC-TOFMS) has been evaluated for the profiling of relatively low-molecular weight protein species in both genetically modified (GM) and non-GM maize. The proposed approach consisted of a straightforward sample fractionation with different water and ethanol-based buffer solutions followed by separation and detection of the protein species using liquid chromatography with a small particle size (1.8 μm) C(18) column and electrospray-time-of-flight mass spectrometry detection in the positive ionization mode. The fractionation of maize reference material containing different content of transgenic material (from 0 to 5% GM) led to five different fractions (albumins, globulins, zeins, zein-like glutelins, and glutelins), all of them containing different protein species (from 2 to 52 different species in each fraction). Some relevant differences in the quantity and types of protein species were observed in the different fractions of the reference material (with different GM contents) tested, thus revealing the potential use of the proposed approach for fast protein profiling and to detect tentative GMO markers in maize.
Reichwald, Kirsten; Hatzack, Frank
A modified version of the Haug and Lantzsch method for rapid photometrical phytate determination was applied for the analysis of phytate in soybean, wheat, and maize meals. In comparison to the original protocol, the amount of the toxic reagent thioglycolic acid is reduced substantially to minimize potential health risks for laboratory personnel. Different extraction conditions for soybean meal were tested, and boiling for at least 30 min was found to be necessary to remove an interfering compound in soybean meal extracts. Phytate contents determined according to the modified Haug and Lantzsch method did not differ from those obtained by measuring total precipitated phosphorus or by sensitive and specific high-performance ion chromatography. Applicability and accuracy of the modified method for phytate analysis in major feed substrates, including soy-based textured vegetable protein, were demonstrated.
Pauly, Markus; Hake, Sarah; Kraemer, Florian J
The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.
Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka
Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses.
Scott-Craig, J S; Casida, J E; Poduje, L; Walton, J D
Dichloroacetamide safeners protect maize (Zea mays L.) against injury from chloroacetanilide and thiocarbamate herbicides. Etiolated maize seedlings have a high-affinity cytosolic-binding site for the safener [3H](R,S)-3-dichloroacetyl-2,2,5-trimethyl-1, 3-oxazol-idine ([3H]Saf), and this safener-binding activity (SafBA) is competitively inhibited by the herbicides. The safener-binding protein (SafBP), purified to homogeneity, has a relative molecular weight of 39,000, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an isoelectric point of 5.5. Antiserum raised against purified SafBP specifically recognizes a 39-kD protein in etiolated maize and sorghum (Sorghum bicolor L.), which have SafBA, but not in etiolated wheat (Triticum aestivum L.), oat (Avena sativa L.), barley (Hordeum vulgare L.), tobacco (Nicotiana tabacum L.), or Arabidopsis, which lack SafBA. SafBP is most abundant in the coleoptile and scarcest in the leaves, consistent with the distribution of SafBA. SBP1, a cDNA encoding SafBP, was cloned using polymerase chain reaction primers based on purified proteolytic peptides. Extracts of Escherichia coli cells expressing SBP1 have strong [3H]Saf binding, which, like binding to the native maize protein, is competitively inhibited by the safener dichlormid and the herbicides S-ethyl dipropylthiocarbamate, alachlor, and metolachlor. SBP1 is predicted to encode a phenolic O-methyltransferase, but SafBP does not O-methylate catechol or caffeic acid. The acquisition of its encoding gene opens experimental approaches for the evaluation of the role of SafBP in response to the relevant safeners and herbicides.
Wang, Hai; Huang, Dafang; Lang, Zhihong
In the transformation of multiple genes, gene fusion is an attractive alternative to other methods, including sexual crossing, re-transformation, and co-transformation, among others. The 2A peptide from the foot-and-mouth disease virus (FMDV) causes the co-translational “cleavage” of polyprotein and operates in a wide variety of eukaryotic cells. LP4, a linker peptide that originates from a natural polyprotein occurring in the seed of Impatiens balsamina, can be split between the first and second amino acids in post-translational processing. LP4/2A is a hybrid linker peptide that contains the first nine amino acids of LP4 and 20 amino acids of 2A. The three linkers have been used as a suitable technique to link the expression of genes in some transgenic plants, but to date the cleavage efficiency of three linkers have not been comprehensively demonstrated in the same transformation system, especially in the staple crop. To verify the functions of 2A, LP4, and LP4/2A linker peptides in transgenic maize, six fusion protein vectors that each encoded a single open reading frame (ORF) incorporating two report genes, Green Fluorescent Protein (GFP) and β-glucuronidase (GUS), separated by 2A (or modified 2A), LP4 or LP4/2A were assembled to compare the cleavage efficiency of the three linkers in a maize transient expression system. The results demonstrated the more protein production and higher cleavage splicing efficiency with the polyprotein construct linked by the LP4/2A peptide than those of the polyprotein constructs linked by 2A or LP4 alone. Seven other fusion proteins that each encoded a single ORF incorporating two different genes GFP and Red Fluorecent Protein (RFP) with different signal peptides were assembled to study the subcellular localization of genes linked by LP4/2A. The subcellular localization experiments suggested that both types of signal peptide, co-translational and post-translational, could lead their proteins to the target localization in
Paul, Vijay; Guertler, Patrick; Wiedemann, Steffi; Meyer, Heinrich H D
To investigate the relative degradation and fragmentation pattern of the recombinant Cry1Ab protein from genetically modified (GM) maize MON810 throughout the gastrointestinal tract (GIT) of dairy cows, a 25 months GM maize feeding study was conducted on 36 lactating Bavarian Fleckvieh cows allocated into two groups (18 cows per group) fed diets containing either GM maize MON810 or nearly isogenic non-GM maize as the respective diet components. All cows were fed a partial total mixed ration (pTMR). During the feeding trial, 8 feed (4 transgenic (T) and 4 non-transgenic (NT) pTMR) and 42 feces (26 T and 18 NT) samples from the subset of cows fed T and NT diets, and at the end of the feeding trial, digesta contents of rumen, abomasum, small intestine, large intestine and cecum were collected after the slaughter of six cows of each feeding group. Samples were analyzed for Cry1Ab protein and total protein using Cry1Ab specific ELISA and bicinchoninic acid assay, respectively. Immunoblot analyses were performed to evaluate the integrity of Cry1Ab protein in feed, digesta and feces samples. A decrease to 44% in Cry1Ab protein concentration from T pTMR to the voided feces (9.40 versus 4.18 mug/g of total proteins) was recorded. Concentrations of Cry1Ab protein in GIT digesta of cows fed T diets varied between the lowest 0.38 mug/g of total proteins in abomasum to the highest 3.84 mug/g of total proteins in rumen. Immunoblot analysis revealed the extensive degradation of recombinant Cry1Ab protein into a smaller fragment of around 34 kDa in GIT. The results of the present study indicate that the recombinant Cry1Ab protein from MON810 is increasingly degraded into a small fragment during dairy cow digestion.
Chang, Yujie; Shen, Erli; Wen, Liuying; Yu, Jingjuan; Zhu, Dengyun; Zhao, Qian
Lysine is the most limiting essential amino acid for animal nutrition in maize grains. Expression of naturally lysine-rich protein genes can increase the lysine and protein contents in maize seeds. AtMAP18 from Arabidopsis thaliana encoding a microtubule-associated protein with high-lysine content was introduced into the maize genome with the seed-specific promoter F128. The protein and lysine contents of different transgenic offspring were increased prominently in the six continuous generations investigated. Expression of AtMAP18 increased both zein and non-zein protein in the transgenic endosperm. Compared with the wild type, more protein bodies were observed in the endosperm of transgenic maize. These results implied that, as a cytoskeleton binding protein, AtMAP18 facilitated the formation of protein bodies, which led to accumulation of both zein and non-zein proteins in the transgenic maize grains. Furthermore, F1 hybrid lines with high lysine, high protein and excellent agronomic traits were obtained by hybridizing T6 transgenic offspring with other wild type inbred lines. This article provides evidence supporting the use of cytoskeleton-associated proteins to improve the nutritional value of maize. PMID:26580206
Liu, Chen; Li, Shixue; Yue, Jing; Xiao, Wenhan; Zhao, Qian; Zhu, Dengyun; Yu, Jingjuan
Maize (Zea mays) seed is deficient in protein and lysine content. Many studies have been made to improve the nutritional quality of maize seeds. Previously, we reported the role of a natural lysine-rich protein gene SBgLR in increasing protein and lysine content. However, how the SBgLR improves lysine and protein content remains unclear. Here, the reasons and possible mechanism for SBgLR in protein and lysine improvement have been analyzed and discussed. Through seed-specific expression of SBgLR, we obtained transgenic maize with the simultaneously increased lysine and protein contents. High-protein and high-lysine characters were stably inherited across generations. The expression of SBgLR in maize kernels increased the accumulation of both zeins and non-zein proteins. Transmission electron microscopy showed that the number of protein bodies (PBs) was increased obviously in SBgLR transgenic immature endosperms with the morphology and structure of PBs unchanged. The proteinaceous matrix was more abundant in transgenic mature endosperms under scanning electron microscopy. The stabilities of zein and lysine-rich non-zein genes were also increased in transgenic endosperms. Finally, the potential application of SBgLR in maize nutrient improvement was evaluated. This study shows that a cytoskeleton-associated protein has potential applicable value in crop nutrient improving, and provided a feasible strategy for improvement of maize grain quality. PMID:26703573
Zhao, Yang; Zhou, Yuqiong; Jiang, Haiyang; Li, Xiaoyu; Gan, Defang; Peng, Xiaojian; Zhu, Suwen; Cheng, Beijiu
Background Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). Methods and Findings In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related cis-elements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution. Conclusions Our results reveal a comprehensive overview of the maize HD-Zip gene family and provide the first step towards the selection of Zmhdz genes for cloning and functional research to uncover their roles in maize growth and development. PMID:22164299
Guo, Baojian; Chen, Yanhong; Li, Chuan; Wang, Tianya; Wang, Rui; Wang, Bo; Hu, Sha; Du, Xiaofen; Xing, Hongyan; Song, Xiao; Yao, Yingyin; Sun, Qixin; Ni, Zhongfu
To better understand the underlying molecular basis of leaf development in maize, a reference map of nuclear proteins in basal region of seedling leaf was established using a combination of 2DE and MALDI-TOF-MS. In total, 441 reproducible protein spots in nuclear proteome of maize leaf basal region were detected with silver staining in a pH range of 3-10, among which 203 spots corresponding to 163 different proteins were identified. As expected, proteins implicated in RNA and protein-associated functions were overrepresented in nuclear proteome. Remarkably, a high percentage (10%) of proteins was identified to be involved in cell division and growth. In addition, comparative nuclear proteomic analysis in leaf basal region of highly heterotic hybrid Mo17/B73 and its parental lines was also performed and 52 of 445 (11.69%) detected protein spots were differentially expressed between the hybrid and its parental lines, among which 16 protein spots displayed nonadditively expressed pattern. These results indicated that hybridization between two parental lines can cause changes in the expression of a variety of nuclear proteins, which may be responsible for the observed leaf size heterosis.
Water-deficit stress tolerance is a complex trait, and water deficit results in various physiological and chemical changes in maize (Zea mays L.) and exacerbates preharvest aflatoxin contamination. The objective of this study was to characterize the variations in morphology, physiology and gene expr...
Hernández, Marta; Rodríguez-Lázaro, David; Zhang, David; Esteve, Teresa; Pla, Maria; Prat, Salomé
The number of cultured hectares and commercialized genetically modified organisms (GMOs) has increased exponentially in the past 9 years. Governments in many countries have established a policy of labeling all food and feed containing or produced by GMOs. Consequently, versatile, laboratory-transferable GMO detection methods are in increasing demand. Here, we describe a qualitative PCR-based multiplex method for simultaneous detection and identification of four genetically modified maize lines: Bt11, MON810, T25, and GA21. The described system is based on the use of five primers directed to specific sequences in these insertion events. Primers were used in a single optimized multiplex PCR reaction, and sequences of the amplified fragments are reported. The assay allows amplification of the MON810 event from the 35S promoter to the hsp intron yielding a 468 bp amplicon. Amplification of the Bt11 and T25 events from the 35S promoter to the PAT gene yielded two different amplicons of 280 and 177 bp, respectively, whereas amplification of the 5' flanking region of the GA21 gave rise to an amplicon of 72 bp. These fragments are clearly distinguishable in agarose gels and have been reproduced successfully in a different laboratory. Hence, the proposed method comprises a rapid, simple, reliable, and sensitive (down to 0.05%) PCR-based assay, suitable for detection of these four GM maize lines in a single reaction.
Ahmad, Rafiq; Zuily-Fodil, Yasmine; Passaquet, Chantal; Ali Khan, Sabaz; Repellin, Anne
In this study, a full-length cDNA encoding a novel phytocystatin gene, designated CC14, was identified in maize leaves. The CC14 gene sequence reported in this study has been deposited in the GenBank database (accession number JF290478). The CC14 gene was cloned into an expression vector pET30 EK/LIC and was then transformed into Escherichia coli strain BL21 (DE3) pLysS to produce a recombinant CC14 protein. The recombinant protein was purified by nickel nitrilotriacetic acid affinity chromatography after induction with 1 mM IPTG. The purified CC14 protein was electrophoresed on SDS-PAGE and a protein 25 kDa in size was observed. Antiprotease activities of the purified recombinant CC14 protein against cysteine proteases and commercially available papain were tested. The results showed that CC14 purified protein suppressed 100% activity of papain and 57-86% plant cysteine protease activity. Moreover, an upregulation of CC14 gene expression was observed after 20 days of ozone stress in maize leaves. Together, these observations concurred to conclude that CC14 gene could potentially be used as a basis for the development of transgenic crops and natural pesticides that resist biotic and abiotic stresses.
Maschietto, Valentina; Lanubile, Alessandra; Leonardis, Silvana De; Marocco, Adriano; Paciolla, Costantino
Fusarium verticillioides is a fungal pathogen of maize that causes ear rot and contaminates the grains with fumonisin mycotoxins. Breeding for resistance to Fusarium emerged as the most economic and environmentally safe strategy; therefore the discovery of resistant sources and effective molecular markers are a priority. Ears of resistant (CO441 and CO433) and susceptible (CO354 and CO389) maize lines were inoculated with F. verticillioides and the expression of pathogenesis-related (PR) genes (PR1, PR5, PRm3, PRm6) and genes that protect from oxidative stress (peroxidase, catalase, superoxide dismutase and ascorbate peroxidase) were evaluated in the kernels at 72h post inoculation. In addition, the oxidation level and the enzymatic activity of ascorbate-glutathione cycle, catalase, superoxide dismutase and cytosolic and wall peroxidases were investigated. The uninoculated kernels of the resistant lines showed higher gene expression and enzymatic activities, highlighting the key role of constitutive resistance in limiting pathogen attack. In contrast, the susceptible lines activated defensive genes only after pathogen inoculation, resulting in increased levels of H2O2 and lipid peroxidation, as well as lower enzymatic activities. The constitutive defenses observed in this study from seed could be profitably exploited to develop markers to speed up conventional breeding programs in the selection of resistant genotypes.
Rocha, Liliana O.; Barroso, Vinícius M.; Andrade, Ludmila J.; Pereira, Gustavo H. A.; Ferreira-Castro, Fabiane L.; Duarte, Aildson P.; Michelotto, Marcos D.; Correa, Benedito
This study aimed to determine the levels of fumonisins produced by Fusarium verticillioides and FUM gene expression on Bt (Bacillus thuringiensis) and non-Bt maize, post harvest, during different periods of incubation. Transgenic hybrids 30F35 YG, 2B710 Hx and their isogenic (30F35 and 2B710) were collected from the field and a subset of 30 samples selected for the experiments. Maize samples were sterilized by gamma radiation at a dose of 20 kGy. Samples were then inoculated with F. verticillioides and analyzed under controlled conditions of temperature and relative humidity for fumonisin B1 and B2 (FB1 and FB2) production and FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15, and FUM19 expression. 2B710 Hx and 30F35 YG kernel samples were virtually intact when compared to the non-Bt hybrids that came from the field. Statistical analysis showed that FB1 production was significantly lower in 30F35 YG and 2B710 Hx than in the 30F35 and 2B710 hybrids (P < 0.05). However, there was no statistical difference for FB2 production (P > 0.05). The kernel injuries observed in the non-Bt samples have possibly facilitated F. verticillioides penetration and promoted FB1 production under controlled conditions. FUM genes were expressed by F. verticillioides in all of the samples. However, there was indication of lower expression of a few FUM genes in the Bt hybrids; and a weak association between FB1 production and the relative expression of some of the FUM genes were observed in the 30F35 YG hybrid. PMID:26779158
Rocha, Liliana O; Barroso, Vinícius M; Andrade, Ludmila J; Pereira, Gustavo H A; Ferreira-Castro, Fabiane L; Duarte, Aildson P; Michelotto, Marcos D; Correa, Benedito
This study aimed to determine the levels of fumonisins produced by Fusarium verticillioides and FUM gene expression on Bt (Bacillus thuringiensis) and non-Bt maize, post harvest, during different periods of incubation. Transgenic hybrids 30F35 YG, 2B710 Hx and their isogenic (30F35 and 2B710) were collected from the field and a subset of 30 samples selected for the experiments. Maize samples were sterilized by gamma radiation at a dose of 20 kGy. Samples were then inoculated with F. verticillioides and analyzed under controlled conditions of temperature and relative humidity for fumonisin B1 and B2 (FB1 and FB2) production and FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15, and FUM19 expression. 2B710 Hx and 30F35 YG kernel samples were virtually intact when compared to the non-Bt hybrids that came from the field. Statistical analysis showed that FB1 production was significantly lower in 30F35 YG and 2B710 Hx than in the 30F35 and 2B710 hybrids (P < 0.05). However, there was no statistical difference for FB2 production (P > 0.05). The kernel injuries observed in the non-Bt samples have possibly facilitated F. verticillioides penetration and promoted FB1 production under controlled conditions. FUM genes were expressed by F. verticillioides in all of the samples. However, there was indication of lower expression of a few FUM genes in the Bt hybrids; and a weak association between FB1 production and the relative expression of some of the FUM genes were observed in the 30F35 YG hybrid.
Aspergillus flavus and Fusariumverticillioides are fungal pathogens that colonize maize seeds and contaminate them with mycotoxins. To investigate the plant microbe interactions, we conducted histological and molecular studies to characterize the internal colonization of maize seed by the two fungal...
Ludwig, Yvonne; Zhang, Yanxiang; Hochholdinger, Frank
The plant hormone auxin plays a key role in the coordination of many aspects of growth and development. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) genes encode instable primary auxin responsive regulators of plant development that display a protein structure with four characteristic domains. In the present study, a comprehensive analysis of the 34 members of the maize Aux/IAA gene family was performed. Phylogenetic reconstructions revealed two classes of Aux/IAA proteins that can be distinguished by alterations in their domain III. Seven pairs of paralogous maize Aux/IAA proteins were discovered. Comprehensive root-type and tissue-specific expression profiling revealed unique expression patterns of the diverse members of the gene family. Remarkably, five of seven pairs of paralogous genes displayed highly correlated expression patterns in roots. All but one (ZmIAA23) tested maize Aux/IAA genes were auxin inducible, displaying two types of auxin induction within three hours of treatment. Moreover, 51 of 55 (93%) differential Aux/IAA expression patterns between different root-types followed the expression tendency: crown roots > seminal roots > primary roots > lateral roots. This pattern might imply root-type-specific regulation of Aux/IAA transcript abundance. In summary, the detailed analysis of the maize Aux/IAA gene family provides novel insights in the evolution and developmental regulation and thus the function of these genes in different root-types and tissues.
Vaïtilingom, M; Pijnenburg, H; Gendre, F; Brignon, P
A fast and quantitative method was developed to detect transgenic "Maximizer" maize "event 176" (Novartis) and "Roundup Ready" soybean (Monsanto) in food by real-time quantitative PCR. The use of the ABI Prism 7700 sequence detection system allowed the determination of the amplified product accumulation through a fluorogenic probe (TaqMan). Fluorescent dyes were chosen in such a way as to coamplify total and transgenic DNA in the same tube. Using real-time quantitative PCR, 2 pg of transgenic or total DNA per gram of starting sample was detected in 3 h after DNA extraction and the relative amounts of "Maximizer" maize and "Roundup Ready" soybean in some representative food products were quantified.
Casati, Paula; Walbot, Virginia
Microarray hybridization was used to assess acclimation responses to four UV regimes by near isogenic maize (Zea mays) lines varying in flavonoid content. We found that 355 of the 2,500 cDNAs tested were regulated by UV radiation in at least one genotype. Among these, 232 transcripts are assigned putative functions, whereas 123 encode unknown proteins. UV-B increased expression of stress response and ribosomal protein genes, whereas photosynthesis-associated genes were down-regulated; lines lacking UV-absorbing pigments had more dramatic responses than did lines with these pigments, confirming the shielding role of these compounds. Sunlight filtered to remove UV-B or UV-B plus UV-A resulted in significant expression changes in many genes not previously associated with UV responses. Some pathways regulated by UV radiation are shared with defense, salt, and oxidative stresses; however, UV-B radiation can activate additional pathways not shared with other stresses. PMID:12913132
Verhovez, A; Williams, T A; Morello, F; Monticone, S; Brizzi, M F; Dentelli, P; Fallo, F; Fabris, B; Amenta, F; Gomez-Sanchez, C; Veglio, F; Mulatero, P
The toxic effects of aldosterone on the vasculature, and in particular on the endothelial layer, have been proposed as having an important role in the cardiovascular pathology observed in mineralocorticoid-excess states. In order to characterize the genomic molecular mechanisms driving the aldosterone-induced endothelial dysfunction, we performed an expression microarray on transcripts obtained from both human umbilical vein endothelial cells and human coronary artery endothelial cells stimulated with 10 - 7 M aldosterone for 18 h. The results were then subjected to qRT-PCR confirmation, also including a group of genes known to be involved in the control of the endothelial function or previously described as regulated by aldosterone. The state of activation of the mineralocorticoid receptor was investigated by means of a luciferase-reporter assay using a plasmid encoding a mineralocorticoid and glucocorticoid-sensitive promoter. Aldosterone did not determine any significant change in gene expression in either cell type both in the microarray and in the qRT-PCR analysis. The luciferase-reporter assay showed no activation of the mineralocorticoid receptor following aldosterone stimulation. The status of nonfunctionality of the mineralocorticoid receptor expressed in cultured human umbilical and coronary artery endothelial cells does not allow aldosterone to modify gene expression and provides evidence against either a beneficial or harmful genomic effect of aldosterone on healthy endothelial cells.
Dijk, Jeroen P van; Leifert, Carlo; Barros, Eugenia; Kok, Esther J
Since the mid 1990s, microarray analysis has become one of the few tools that can analyze the entire contents of a cell regarding a specific information type. Especially since the development of whole genome microarrays the technique can be considered truly holistic. Most DNA based microarrays are used for the analysis of the total of messenger RNAs (transcriptome) and provide a snap-shot of what's going on in a cell population at the time of sampling. Within the last few years also full genome plant microarrays have become available for several crop species. With these it has been shown that several growing conditions can be separated based on their transcriptome pattern, such as location, year of harvest and agricultural input system, but also different cultivars of the same crop species, including genetically modified ones. A database comprising expression levels of the transcriptome in many different circumstances with a history of safe use would be a good comparator for evaluation of new agricultural practices or cultivars, genetically modified or otherwise obtained. New techniques as next generation sequencing may overcome issues on throughput time and cost, standard operation procedures and array design for individual crops.
Sun, Wei; Chen, Hao; Wang, Juan; Sun, Hong Wei; Yang, Shu Ke; Sang, Ya Lin; Lu, Xing Bo; Xu, Xiao Hui
Mitogen-activated protein kinases (MAPKs) play important roles in stress responses and development in plants. Maize (Zea mays), an important cereal crop, is a model plant species for molecular studies. In the last decade, several MAPKs have been identified in maize; however, their functions have not been studied extensively. Genome-wide identification and expression analysis of maize MAPK genes could provide valuable information for understanding their functions. In this study, 20 non-redundant maize MAPK genes (ZmMPKs) were identified via a genome-wide survey. Phylogenetic analysis of MAPKs from maize, rice (Oryza sativa), Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), and tomato (Solanum lycopersicum) classified them into four major classes. ZmMPKs in the same class had similar domains, motifs, and genomic structures. Gene duplication investigations suggested that segmental duplications made a large contribution to the expansion of ZmMPKs. A number of cis-acting elements related to plant development and response to stress and hormones were identified in the promoter regions of ZmMPKs. Furthermore, transcript profile analysis in eight tissues and organs at various developmental stages demonstrated that most ZmMPKs were preferentially expressed in reproductive tissues and organs. The transcript abundance of most ZmMPKs changed significantly under salt, drought, cold, or abscisic acid (ABA) treatments, implying that they might participate in abiotic stress and ABA signaling. These expression analyses indicated that ZmMPKs might serve as linkers between abiotic stress signaling and plant reproduction. Our data will deepen our understanding of the complexity of the maize MAPK gene family and provide new clues to investigate their functions.
Yandeau-Nelson, Marna D.; Nikolau, Basil J.; Schnable, Patrick S.
Meiotic recombination rates are potentially affected by cis- and trans-acting factors, i.e., genotype-specific modifiers that do or do not reside in the recombining interval, respectively. Effects of trans modifiers on recombination across the ∼140-kb maize a1–sh2 interval of chromosome 3L were studied in the absence of polymorphic cis factors in three genetically diverse backgrounds into which a sequence-identical a1–sh2 interval had been introgressed. Genetic distances across a1–sh2 varied twofold among genetic backgrounds. Although the existence of regions exhibiting high and low rates of recombination (hot and cold spots, respectively) was conserved across backgrounds, the absolute rates of recombination in these sequence-identical regions differed significantly among backgrounds. In addition, an intergenic hot spot had a higher rate of recombination as compared to the genome average rate of recombination in one background and not in another. Recombination rates across two genetic intervals on chromosome 1 did not exhibit the same relationships among backgrounds as was observed in a1–sh2. This suggests that at least some detected trans-acting factors do not equally affect recombination across the genome. This study establishes that trans modifier(s) polymorphic among genetic backgrounds can increase and decrease recombination in both genic and intergenic regions over relatively small genetic and physical intervals. PMID:16816431
Xin, Mingming; Yang, Ruolin; Li, Guosheng; Chen, Hao; Laurie, John; Ma, Chuang; Wang, Dongfang; Yao, Yingyin; Larkins, Brian A.; Sun, Qixin; Yadegari, Ramin; Wang, Xiangfeng; Ni, Zhongfu
In angiosperms, the endosperm provides nutrients for embryogenesis and seed germination and is the primary tissue where gene imprinting occurs. To identify the imprintome of early developing maize (Zea mays) endosperm, we performed high-throughput transcriptome sequencing of whole kernels at 0, 3, and 5 d after pollination (DAP) and endosperms at 7, 10, and 15 DAP, using B73 by Mo17 reciprocal crosses. We observed gradually increased expression of paternal transcripts in 3- and 5-DAP kernels. In 7-DAP endosperm, the majority of the genes tested reached a 2:1 maternal versus paternal ratio, suggesting that paternal genes are nearly fully activated by 7 DAP. A total of 116, 234, and 63 genes exhibiting parent-specific expression were identified at 7, 10, and 15 DAP, respectively. The largest proportion of paternally expressed genes was at 7 DAP, mainly due to the significantly deviated parental allele expression ratio of these genes at this stage, while nearly 80% of the maternally expressed genes (MEGs) were specific to 10 DAP and were primarily attributed to sharply increased expression levels compared with the other stages. Gene ontology enrichment analysis of the imprinted genes suggested that 10-DAP endosperm-specific MEGs are involved in nutrient uptake and allocation and the auxin signaling pathway, coincident with the onset of starch and storage protein accumulation. PMID:24058158
The classical maize mutant iojap (Iodent japonica) has variegated green and white leaves. Green sectors have cells with normal chloroplasts whereas white sectors have cells where plastids fail to differentiate. These mutant plastids, when transmitted through the female gametophyte, do not recover in the presence of wild type Iojap. We cloned the Ij locus, and we have investigated the mechanism of epigenetic inheritance and phenotypic expression. More recently, a modifier of this type of variegation, ''Inhibitor of striate'', has also been cloned. Both the iojap and inhibitor of striate proteins have homologs in bacteria and are members of ancient conserved families found in multiple species. These tools can be used to address fundamental questions of inheritance and variegation associated with this classical conundrum of maize genetics. Since the work of Rhoades there has been considerable speculation concerning the nature of the Iojap gene product, the origin of leaf variegation and the mechanism behind the material inheritance of defective plastids. This has made Iojap a textbook paradigm for cytoplasmic inheritance and nuclear-organellar interaction for almost 50 years. Cloning of the Iojap gene in maize, and homologs in other plants and bacteria, provides a new means to address the origin of heteroplastidity, variegation and cytoplasmic inheritance in higher plants.
Konstantinov, K; Mladenović, S; Stojkov, S; Delić, N; Gosić, S; Petrović, R; Lević, J; Denić, M
Results obtained by several approaches in the application of Biotechnology in maize breeding are reviewed. RFLP technology in the determination of genetic variation; gene transfer by the use of different methods of gene delivery and the determination of gene integration. Three technologies for foreign gene introduction have been applied; injection of plasmid pRT100 neo into archesporial tissue before micro and macro sporogenesis, slightly modified pollen-tube pathway technology and dry seed incubation in plasmid DNA solution. NPTII gene integration was followed by dot-blot and Southern blot analysis of plant DNA of both T1 and T2 plants. Gene expression was analysed by neomycin phosphotransferase activity. Transformed plants contained the selective NPTII gene sequence in an active form. Bacterial gene integration induced several heritable changes of plant phenotype. As an important change, alteration of the flowering time has been used as a criterion for selection and plant propagation to keep transformed progeny. Besides plant genome transformation, endogenous bacteria living in different maize tissue were found. As a perspective approach for biotechnology application in maize breeding biological vaccine construction has been selected. Therefore, antagonistic effect of gram positive bacterial strains to several pathogenic fungi was investigated. Results obtained after in vivo experiments are discussed.
Stupar, Robert M; Springer, Nathan M
Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73xMo17 and Mo17xB73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The approximately 20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns.
Nazir, Muslima; Pandey, Renu; Siddiqi, Tariq O.; Ibrahim, Mohamed M.; Qureshi, Mohammad I.; Abraham, Gerard; Vengavasi, Krishnapriya; Ahmad, Altaf
Nitrogen (N) is essential for proper plant growth and its application has proven to be critical for agricultural produce. However, for unavoidable economic and environmental problems associated with excessive use of N-fertilizers, it is an urgent demand to manage application of fertilizers. Improving the N-use efficiency (NUE) of crop plants to sustain productivity even at low N levels is the possible solution. In the present investigation, contrasting low-N sensitive (HM-4) and low-N tolerant (PEHM-2) genotypes were identified and used for comparative proteome-profiling of leaves under optimum and low N as well as restoration of low N on 3rd (NR3) and 5th (NR5) days after re-supplying N. The analysis of differential expression pattern of proteins was performed by 2-D gel electrophoresis. Significant variations in the expression of proteins were observed under low N, which were genotype specific. In the leaf proteome, 25 spots were influenced by N treatment and four spots were different between the two genotypes. Most of the proteins that were differentially accumulated in response to N level and were involved in photosynthesis and metabolism, affirming the relationship between N and carbon metabolism. In addition to this, greater intensity of some defense proteins in the low N tolerant genotype was found that may have a possible role in imparting it tolerance under N starvation conditions. The new insights generated on maize proteome in response to N-starvation and restoration would be useful toward improvement of NUE in maize. PMID:27047497
Shen, Yaou; Zhang, Yongzhong; Chen, Jie; Lin, Haijian; Zhao, Maojun; Peng, Huanwei; Liu, Li; Yuan, Guangsheng; Zhang, Suzhi; Zhang, Zhiming; Pan, Guangtang
Lead (Pb) has become one of the most abundant heavy metal pollutants of the environment. With its large biomass, maize could be an important object for studying the phytoremediation of Pb-contaminated soil. In our previous research, we screened 19 inbred lines of maize for Pb concentration, and line 178 was identified to be a hyperaccumulator for Pb in both the roots and aboveground parts. To identify important genes and metabolic pathways related to Pb accumulation and tolerance, line 178 was underwent genome expression profile under Pb stress and a control (CK). A total of approximately 11 million cDNA tags were sequenced and 4 665 539 and 4 936 038 clean tags were obtained from the libraries of the test and CK, respectively. In comparison to CK, 2379 and 1832 genes were identified up- or downregulated, respectively, more than fivefolds under Pb stress. Interestingly, all the genes were related to cellular processes and signaling, information storage and processing or metabolism functions. Particularly, the genes involved in posttranslational modification, protein turnover and chaperones; signal transduction, carbohydrate transport and metabolism; and lipid transport and metabolism significantly changed under the treatment. In addition, seven pathways including ribosome, photosynthesis, and carbon fixation were affected significantly, with 118, 12, 34, 21, 18, 72 and 43 differentially expressed genes involved. The significant upregulation of the ribosome pathway may reveal an important secret for Pb tolerance of line 178. And the sharp increase of laccase transcripts and metal ion transporters were suggested to account in part for Pb hyperaccumulation in the line.
Santi, Simonetta; Locci, Geraldine; Monte, Rossella; Pinton, Roberto; Varanini, Zeno
An investigation was carried out to assess the effect of nitrate supply on the root plasma membrane (PM) H+-ATPase of etiolated maize (Zea mays L.) seedlings grown in hydroponics. The treatment induced higher uptake rates of the anion and the expression of a putative high-affinity nitrate transporter gene (ZmNRT2.1), the first to be identified in maize. Root PM H+-ATPase activity displayed a similar time-course pattern as that of net nitrate uptake and investigations were carried out to determine which of the two isoforms reported to date in maize, MHA1 and 2, responded to the treatment. MHA1 was not expressed under the conditions analysed. Genome analysis revealed that MHA2, described as the most abundant form in all maize tissues, was not present in the maize hybrid investigated, but a similar form was found instead and named MHA3. A second gene (named MHA4) was also identified and partially sequenced. Both genes, classified as members of the PM H+-ATPase subfamily II, responded to nitrate supply, although to different degrees: MHA4, in particular, proved more sensitive than MHA3, with a greater up- and down-regulation in response to the treatment. Increased expression of subfamily II genes resulted in higher steady-state levels of the enzyme in the root tissues and enhanced ATP-hydrolysing activity. The results support the idea that greater proton-pumping activity is required when nitrate inflow increases and suggest that nitrate may be the signal triggering the expression of the two members of PM H+-ATPase subfamily II.
Vaculík, Marek; Pavlovič, Andrej; Lux, Alexander
Silicon was shown to alleviate the negative effects of various biotic and abiotic stresses on plant growth. Although the positive role of Si on toxic and heavy metal Cd has been already described, the mechanisms have been explained only partially and still remain unclear. In the present study we investigated the effect of Si on photosynthetic-related processes in maize exposed to two different levels of Cd via measurements of net photosynthetic rate (AN), chlorophyll a fluorescence and pigment analysis, as well as studies of leaf tissue anatomy and cell ultrastructure using bright-field and transmission electron microscopy. We found that Si actively alleviated the toxic syndromes of Cd by increasing AN, effective photochemical quantum yield of photosystem II (ϕPSII) and content of assimilation pigments, although did not decrease the concentration of Cd in leaf tissues. Cadmium did not affect the leaf anatomy and ultrastructure of leaf mesophyll's cell chloroplasts; however, Cd negatively affected thylakoid formation in chloroplasts of bundle sheath cells, and this was alleviated by Si. Improved thylakoid formation in bundle sheath's cell chloroplasts may contribute to Si-induced enhancement of photosynthesis and related increase in biomass production in C4 plant maize.
Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Lanz, Christa
Heterosis is the superior performance of F1 hybrids compared with their homozygous, genetically distinct parents. In this study, we monitored the transcriptomic divergence of the maize (Zea mays) inbred lines B73 and Mo17 and their reciprocal F1 hybrid progeny in primary roots under control and water deficit conditions simulated by polyethylene glycol treatment. Single-parent expression (SPE) of genes is an extreme instance of gene expression complementation, in which genes are active in only one of two parents but are expressed in both reciprocal hybrids. In this study, 1,997 genes only expressed in B73 and 2,024 genes only expressed in Mo17 displayed SPE complementation under control and water deficit conditions. As a consequence, the number of active genes in hybrids exceeded the number of active genes in the parental inbred lines significantly independent of treatment. SPE patterns were substantially more stable to expression changes by water deficit treatment than other genotype-specific expression profiles. While, on average, 75% of all SPE patterns were not altered in response to polyethylene glycol treatment, only 17% of the remaining genotype-specific expression patterns were not changed by water deficit. Nonsyntenic genes that lack syntenic orthologs in other grass species, and thus evolved late in the grass lineage, were significantly overrepresented among SPE genes. Hence, the significant overrepresentation of nonsyntenic genes among SPE patterns and their stability under water limitation might suggest a function of these genes during the early developmental manifestation of heterosis under fluctuating environmental conditions in hybrid progeny of the inbred lines B73 and Mo17. PMID:27999083
Chen, Pingbo; Li, Xia; Huo, Kai; Wei, Xiaodong; Dai, Chuanchao; Lv, Chuangen
We determined the effects of exogenous nitric oxide on photosynthesis and gene expression in transgenic rice plants (PC) over-expressing the maize C4pepc gene, which encodes phosphoenolpyruvate carboxylase (PEPC). Seedlings were subjected to treatments with NO donors, an NO scavenger, phospholipase inhibitors, a Ca(2+) chelator, a Ca(2+) channel inhibitor, and a hydrogen peroxide (H2O2) inhibitor, individually and in various combinations. The NO donors significantly increased the net photosynthetic rate (PN) of PC and wild-type (WT), especially that of PC. Treatment with an NO scavenger did inhibit the PN of rice plants. The treatments with phospholipase inhibitors and a Ca(2+) chelator decreased the PN of WT and PC, and photosynthesis was more strongly inhibited in WT than in PC. Further analyses showed that the NO donors increased endogenous levels of NO and PLD activity, but decreased endogenous levels of Ca(2+) both WT and PC. However, there was a greater increase in NO in WT and a greater increase in PLD activity and Ca(2+) level in PC. The NO donors also increased both PEPC activity and pepc gene expression in PC. PEPC activity can be increased by SNP alone. But the expression of its encoding gene in PC might be regulated by SNP, together with PA and Ca(2+).
Barrieu, François; Chaumont, François; Chrispeels, Maarten J.
Aquaporins are integral membrane proteins of the tonoplast and the plasma membrane that facilitate the passage of water through these membranes. Because of their potentially important role in regulating water flow in plants, studies documenting aquaporin gene expression in specialized tissues involved in water and solute transport are important. We used in situ hybridization to examine the expression pattern of the tonoplast aquaporin ZmTIP1 in different organs of maize (Zea mays L.). This tonoplast water channel is highly expressed in the root epidermis, the root endodermis, the small parenchyma cells surrounding mature xylem vessels in the root and the stem, phloem companion cells and a ring of cells around the phloem strand in the stem and the leaf sheath, and the basal endosperm transfer cells in developing kernels. We postulate that the high level of expression of ZmTIP1 in these tissues facilitates rapid flow of water through the tonoplast to permit osmotic equilibration between the cytosol and the vacuolar content, and to permit rapid transcellular water flow through living cells when required. PMID:9701571
Andrade, T; Von Pinho, E V R; Von Pinho, R G; Oliveira, G E; Andrade, V; Fernandes, J S
We quantified and characterized the expression of heat-resistant proteins during seed development of maize lines with distinct levels of tolerance to high drying temperature. A corn field was planted for multiplication of seeds of different lines, two tolerant and two non-tolerant to high drying temperatures. Harvest of the seeds was carried out at various stages of development and they were then subjected to tests of moisture content, germination, first count of germination, accelerated aging, and cold test. The seeds were stored in a freezer for later analysis of expression of heat-resistant proteins by means of real-time PCR, electrophoresis, and spectrophotometry. We observed that heat-resistant proteins are expressed in a differential manner in seeds from different lines and at different stages of development. The expression of heat-resistant proteins was earlier in lines tolerant to high drying temperatures. Greater germination and vigor values was found for seeds collected at the last stage of development.
Vera, Daniel L; Madzima, Thelma F; Labonne, Jonathan D; Alam, Mohammad P; Hoffman, Gregg G; Girimurugan, S B; Zhang, Jinfeng; McGinnis, Karen M; Dennis, Jonathan H; Bass, Hank W
The eukaryotic genome is organized into nucleosomes, the fundamental units of chromatin. The positions of nucleosomes on DNA regulate protein-DNA interactions and in turn influence DNA-templated events. Despite the increasing number of genome-wide maps of nucleosome position, how global changes in gene expression relate to changes in nucleosome position is poorly understood. We show that in nucleosome occupancy mapping experiments in maize (Zea mays), particular genomic regions are highly susceptible to variation introduced by differences in the extent to which chromatin is digested with micrococcal nuclease (MNase). We exploited this digestion-linked variation to identify protein footprints that are hypersensitive to MNase digestion, an approach we term differential nuclease sensitivity profiling (DNS-chip). Hypersensitive footprints were enriched at the 5' and 3' ends of genes, associated with gene expression levels, and significantly overlapped with conserved noncoding sequences and the binding sites of the transcription factor KNOTTED1. We also found that the tissue-specific regulation of gene expression was linked to tissue-specific hypersensitive footprints. These results reveal biochemical features of nucleosome organization that correlate with gene expression levels and colocalize with functional DNA elements. This approach to chromatin profiling should be broadly applicable to other species and should shed light on the relationships among chromatin organization, protein-DNA interactions, and genome regulation.
This chapter is a succinct overview of maize data held in the species-specific database MaizeGDB (the Maize Genomics and Genetics Database), and selected multi-species data repositories, such as Gramene/Ensembl Plants, Phytozome, UniProt and the National Center for Biotechnology Information (NCBI), ...
Qing, Dong-Jin; Lu, Hai-Feng; Li, Ning; Dong, Hai-Tao; Dong, Deng-Feng; Li, You-Zhi
We studied the transcriptional profiles of leaves and roots of three-leaf stage seedlings of the maize inbred line YQ7-96 under conditions of salt stress (100 mM NaCl) and removal of salt stress (RSS). A total of 296 genes were regulated specifically by the stress, of which 206 were specific to leaves and 90 were specific to roots. Stress-regulated genes were classified into eight and seven expression patterns for leaves and roots, respectively. There were 60 genes which were regulated specifically by RSS, 27 of which were specific to leaves and 33 specific to roots. No genes were found to be co-regulated in tissues and to be regulated commonly by the stress and RSS. It can be concluded that (i) at the early stage of the stress, transcriptional responses are directed at water deficit in maize leaves but at both water deficit and Na+ accumulation in roots; (ii) at the later stage, the responses in leaves and roots result from dual effects of both water deficit and Na+ accumulation; (iii) the polyamine metabolic pathway is an important linker for the co-ordination between leaves and roots to accomplish the tolerance of the whole maize plant to the stress; (iv) the stress can lead to genomic restructuring and nuclear transport in maize; (v) maize leaves are distinct from roots in terms of molecular mechanisms for responses to and growth recovery from the stress; and (vi) mechanisms for the maize responses to the stress differ from those for their growth recovery during RSS.
Boston, R S; Fontes, E B; Shank, B B; Wrobel, R L
Plants carrying floury-2, Defective endosperm-B30, or Mucronate mutations overproduce b-70, a maize homolog of the mammalian immunoglobulin binding protein. During endosperm development in these mutants, levels of both b-70 protein and RNA increase dramatically between 14 days and 20 days after pollination. At later stages, b-70 RNA levels decline while protein levels remain high. The increase in b-70 RNA levels is endosperm specific and dependent on gene dosage in the floury-2 mutant. In all three mutants, the increases in b-70 RNA and protein levels are inversely proportional to changes in zein synthesis. Although b-70 polypeptides can be extracted from purified protein bodies, they carry a carboxy-terminal endoplasmic reticulum retention signal, HDEL. We propose that induction of b-70 in these mutants is a cellular response to abnormally folded or improperly assembled storage proteins and probably reflects its role as a polypeptide chain binding protein. PMID:1840924
Bluhm, Burton H; Dhillon, Braham; Lindquist, Erika A; Kema, Gert HJ; Goodwin, Stephen B; Dunkle, Larry D
Background The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The objectives of this study were to generate a collection of expressed sequence tags (ESTs) from C. zeae-maydis and evaluate their expression during vegetative, infectious, and reproductive growth. Results A total of 27,551 ESTs was obtained from five cDNA libraries constructed from vegetative and sporulating cultures of C. zeae-maydis. The ESTs, grouped into 4088 clusters and 531 singlets, represented 4619 putative unique genes. Of these, 36% encoded proteins similar (E value ≤ 10-05) to characterized or annotated proteins from the NCBI non-redundant database representing diverse molecular functions and biological processes based on Gene Ontology (GO) classification. We identified numerous, previously undescribed genes with potential roles in photoreception, pathogenesis, and the regulation of development as well as Zephyr, a novel, actively transcribed transposable element. Differential expression of selected genes was demonstrated by real-time PCR, supporting their proposed roles in vegetative, infectious, and reproductive growth. Conclusion Novel genes that are potentially involved in regulating growth, development, and pathogenesis were identified in C. zeae-maydis, providing specific targets for characterization by molecular genetics and functional genomics. The EST data establish a foundation for future studies in evolutionary and comparative genomics among species of Cercospora and other groups of plant pathogenic fungi. PMID:18983654
Tungjitwitayakul, Jatuporn; Tatun, Nujira; Vajarasathira, Boongeua; Sakurai, Sho
The maize weevil, Sitophilus zeamais Motschulsky, is a major pest of rice and other postharvest grain stocks in tropical countries. Heating and cooling treatments have been adopted to control this pest. Because heat shock protein (hsp) genes respond to temperature stress, we examined the association of hsp genes with development and thermal stress in S. zeamais. The temperature response of the insect to heat and cold treatments was assessed at four developmental stages: egg, larva, pupa, and adult. LT50 values at high temperatures were similar among the four developmental stages, while adults were the most tolerant to low temperatures, and eggs, larvae, and pupae exhibited similar LT50 values. Expression levels of three hsps--Szhsp70, Szhsc70, and Szhsp90--fluctuated substantially throughout the four stages at a rearing temperature of 28°C. Heat shock and cold shock increased the expression of all three hsps, and the highest upregulation was observed at 40°C, although the intensity of upregulation varied among the three genes: strongly in Szhsp70, moderately in Szhsp90, and slightly in Szhsc70. Basal expression of the three hsps at 28°C and gene responses to heat and cold shock also varied significantly at the tissue level.
Yue, Runqing; Lu, Caixia; Sun, Tao; Peng, Tingting; Han, Xiaohua; Qi, Jianshuang; Yan, Shufeng; Tie, Shuanggui
The calmodulin-binding transcription activators (CAMTA) play critical roles in plant growth and responses to environmental stimuli. However, how CAMTAs function in responses to abiotic and biotic stresses in maize (Zea mays L.) is largely unknown. In this study, we first identified all the CAMTA homologous genes in the whole genome of maize. The results showed that nine ZmCAMTA genes showed highly diversified gene structures and tissue-specific expression patterns. Many ZmCAMTA genes displayed high expression levels in the roots. We then surveyed the distribution of stress-related cis-regulatory elements in the -1.5 kb promoter regions of ZmCAMTA genes. Notably, a large number of stress-related elements present in the promoter regions of some ZmCAMTA genes, indicating a genetic basis of stress expression regulation of these genes. Quantitative real-time PCR was used to test the expression of ZmCAMTA genes under several abiotic stresses (drought, salt, and cold), various stress-related hormones [abscisic acid, auxin, salicylic acid (SA), and jasmonic acid] and biotic stress [rice black-streaked dwarf virus (RBSDV) infection]. Furthermore, the expression pattern of ZmCAMTA genes under RBSDV infection was analyzed to investigate their potential roles in responses of different maize cultivated varieties to RBSDV. The expression of most ZmCAMTA genes responded to both abiotic and biotic stresses. The data will help us to understand the roles of CAMTA-mediated Ca(2+) signaling in maize tolerance to environmental stresses.
Séralini, Gilles-Eric; Mesnage, Robin; Defarge, Nicolas; Gress, Steeve; Hennequin, Didier; Clair, Emilie; Malatesta, Manuela; de Vendômois, Joël Spiroux
Our recent work (Séralini et al., 2012) remains to date the most detailed study involving the life-long consumption of an agricultural genetically modified organism (GMO). This is true especially for NK603 maize for which only a 90-day test for commercial release was previously conducted using the same rat strain (Hammond et al., 2004). It is also the first long term detailed research on mammals exposed to a highly diluted pesticide in its total formulation with adjuvants. This may explain why 75% of our first criticisms arising within a week, among publishing authors, come from plant biologists, some developing patents on GMOs, even if it was a toxicological paper on mammals, and from Monsanto Company who owns both the NK603 GM maize and Roundup herbicide (R). Our study has limits like any one, and here we carefully answer to all criticisms from agencies, consultants and scientists, that were sent to the Editor or to ourselves. At this level, a full debate is biased if the toxicity tests on mammals of NK603 and R obtained by Monsanto Company remain confidential and thus unavailable in an electronic format for the whole scientific community to conduct independent scrutiny of the raw data. In our article, the conclusions of long-term NK603 and Roundup toxicities came from the statistically highly discriminant findings at the biochemical level in treated groups in comparison to controls, because these findings do correspond in an blinded analysis to the pathologies observed in organs, that were in turn linked to the deaths by anatomopathologists. GM NK603 and R cannot be regarded as safe to date.
Tank, Jennifer L.; Rosi-Marshall, Emma J.; Royer, Todd V.; Whiles, Matt R.; Griffiths, Natalie A.; Frauendorf, Therese C.; Treering, David J.
Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape. PMID:20876106
Tank, Jennifer L; Rosi-Marshall, Emma J; Royer, Todd V; Whiles, Matt R; Griffiths, Natalie A; Frauendorf, Therese C; Treering, David J
Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape.
Aflatoxins are carcinogenic toxic compounds produced by Aspergillus flavus during infection of crops including maize (Zea mays L.). Contamination of maize with aflatoxin is exacerbated by late season drought stress. Previous studies have implicated numerous resistance-associated proteins (RAPs) that...
Wang, Hongxia; Yang, Jun; Zhang, Min; Fan, Weijuan; Firon, Nurit; Pattanaik, Sitakanta; Yuan, Ling; Zhang, Peng
There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosynthesis pathway in developing storage roots, leading to greater lignin content in the Lc transgenic lines, compared to the wild type. This was also evidenced by the enhanced lignification of vascular cells in the early storage roots. Furthermore, increased expression of the β-amylase gene in leaves and storage roots also accelerated starch degradation and increased the sugar use efficiency, providing more energy and carbohydrate sources for lignin biosynthesis in the Lc transgenic sweet potato. Lesser starch accumulation was observed in the developing storage roots at the initiation stage in the Lc plants. Our study provides experimental evidence of the basic carbohydrate metabolism underlying the development of storage roots, which is the transformation of lignin biosynthesis to starch biosynthesis.
Wang, Hongxia; Yang, Jun; Zhang, Min; Fan, Weijuan; Firon, Nurit; Pattanaik, Sitakanta; Yuan, Ling; Zhang, Peng
There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosynthesis pathway in developing storage roots, leading to greater lignin content in the Lc transgenic lines, compared to the wild type. This was also evidenced by the enhanced lignification of vascular cells in the early storage roots. Furthermore, increased expression of the β-amylase gene in leaves and storage roots also accelerated starch degradation and increased the sugar use efficiency, providing more energy and carbohydrate sources for lignin biosynthesis in the Lc transgenic sweet potato. Lesser starch accumulation was observed in the developing storage roots at the initiation stage in the Lc plants. Our study provides experimental evidence of the basic carbohydrate metabolism underlying the development of storage roots, which is the transformation of lignin biosynthesis to starch biosynthesis. PMID:26727353
Ronchi, A; Petroni, K; Tonelli, C
The duplicated R and Sn genes regulate the maize anthocyanin biosynthetic pathway and encode tissue-specific products that are homologous to helix-loop-helix transcriptional activators. As a consequence of their coupling in the genome, Sn is partially silenced. Genomic restriction analysis failed to reveal gross structural DNA alterations between the strong original phenotype and the weak derivatives. However, the differences in pigmentation were inversely correlated with differences in the methylation of the Sn promoter. Accordingly, treatment with 5-azacytidine (AZA), a demethylating agent, restored a strong pigmentation pattern that was transmitted to the progeny and that was correlated with differential expression of the Sn transcript. Genomic sequencing confirmed that methylation of the Sn promoter was more apparent in the less pigmented seedlings and was greatly reduced in the AZA revertants. In addition, some methylcytosines were located in non-symmetrical C sequences. These findings provide an insight into Sn and R interaction, a process that we have termed Reduced Expression of Endogenous Duplications (REED). We propose that increasing the copy number of regulatory genes by endogenous duplication leads to such epigenetic mechanisms of silencing. Further understanding of the REED process may have broader implications for gene regulation and may identify new levels of regulation within eukaryotic genomes. Images PMID:7489721
Thirunavukkarasu, Nepolean; Hossain, Firoz; Mohan, Sweta; Shiriga, Kaliyugam; Mittal, Swati; Sharma, Rinku; Singh, Rita Kumari; Gupta, Hari Shankar
Waterlogging causes extensive damage to maize crops in tropical and subtropical regions. The identification of tolerance genes and their interactions at the molecular level will be helpful to engineer tolerant genotypes. A whole-genome transcriptome assay revealed the specific role of genes in response to waterlogging stress in susceptible and tolerant genotypes. Genes involved in the synthesis of ethylene and auxin, cell wall metabolism, activation of G-proteins and formation of aerenchyma and adventitious roots, were upregulated in the tolerant genotype. Many transcription factors, particularly ERFs, MYB, HSPs, MAPK, and LOB-domain protein were involved in regulation of these traits. Genes responsible for scavenging of ROS generated under stress were expressed along with those involved in carbohydrate metabolism. The physical locations of 21 genes expressed in the tolerant genotype were found to correspond with the marker intervals of known QTLs responsible for development of adaptive traits. Among the candidate genes, most showed synteny with genes of sorghum and foxtail millet. Co-expression analysis of 528 microarray samples including 16 samples from the present study generated seven functional modules each in the two genotypes, with differing characteristics. In the tolerant genotype, stress genes were co-expressed along with peroxidase and fermentation pathway genes. PMID:23936429
Plants tolerate water deficits by regulating gene networks controlling cellular and physiological traits to modify growth and development. Transcription factor (TFs) directed regulation of transcription within these gene networks is key to eliciting appropriate responses. In this study, reverse tran...
A member of the maize isopentenyl transferase gene family, Zea mays isopentenyl transferase 2 (ZmIPT2), encodes a cytokinin biosynthetic enzyme expressed during kernel development. Cytokinin biosynthesis in maize.
Brugière, Norbert; Humbert, Sabrina; Rizzo, Nancy; Bohn, Jennifer; Habben, Jeffrey E
Cytokinins (CKs) are plant hormones that regulate a large number of processes associated with plant growth and development such as induction of stomata opening, delayed senescence, suppression of auxin-induced apical dominance, signaling of nitrogen availability, differentiation of plastids and control of sink strength. In maize, CKs are thought to play an important role in establishing seed size and increasing seed set under normal and unfavorable environmental conditions therefore influencing yield. In recent years, the discovery of isopentenyl transferase (IPT) genes in plants has shed light on the CK biosynthesis pathway in plants. In an effort to increase our understanding of the role played by CKs in maize development and sink-strength, we identified several putative IPT genes using a bioinformatics approach. We focused our attention on one gene in particular, ZmIPT2, because of its strong expression in developing kernels. The expression of the gene and its product overlays the change in CK levels in developing kernels suggesting a major role in CK biosynthesis for kernel development. We demonstrate that at 8-10 days after pollination (DAP) the endosperm and especially the basal transfer cell layer (BETL) is a major site of ZmIPT2 expression, and that this expression persists in the BETL and the developing embryo into later kernel development stages. We show that ectopic expression of ZmIPT2 in calli and in planta created phenotypes consistent with CK overproduction. We also show that ZmIPT2 preferentially uses ADP and ATP over AMP as the substrates for dimethylallyl diphosphate (DMAPP) IPT activity. The expression pattern of ZmIPT2 in the BETL, endosperm and embryo during kernel development will be discussed with an emphasis on the suggested role of CKs in determining sink-strength and grain production in crop plants.
Karaman, S; Cunnick, J; Wang, K
The non-toxic B subunit (CT-B) of cholera toxin from Vibrio cholerae is a strong immunogen and amplifies the immune reaction to conjugated antigens. In this work, a synthetic gene encoding for CT-B was expressed under control of a γ-zein promoter in maize seeds. Levels of CT-B in maize plants were determined via ganglioside dependent ELISA. The highest expression level recorded in T(1) generation seeds was 0.0014% of total aqueous soluble protein (TASP). Expression level of the same event in the T(2) generation was significantly increased to 0.0197% of TASP. Immunogenicity of maize derived CT-B was evaluated in mice with an oral immunization trial. Anti-CTB IgG and anti-CTB IgA were detected in the sera and fecal samples of the orally immunized mice, respectively. The mice were protected against holotoxin challenge with CT. An additional group of mice was administrated with an equal amount (5 μg per dose each) of mixed maize-derived CT-B and LT-B (B subunit of E. coli heat labile toxin). In the sera and fecal samples obtained from this group, the specific antibody levels were enhanced compared to either the same or a higher amount of CT-B alone. These results suggest that a synergistic action may be achieved using a CT-B and LT-B mixture that can lead to a more efficacious combined vaccine to target diarrhea induced by both cholera and enterotoxigenic strains of Escherichia coli.
The partially-dominant, autoactive maize disease resistance gene Rp1-D21 causes hypersensitive response (HR) lesions to form spontaneously on the leaves and stem in the absence of pathogen recognition. The maize nested association mapping (NAM) population consists of 25 200-line subpopulations each...
Certified reference materials (CRMs) are required to guarantee the reliability of analytical measurements. The CRMs available in the field of genetically modified organisms (GMOs) are characterized using real-time polymerase chain reaction (qPCR). This technology has limited application, because of its dependence on a calibrant. The objective of this study was to obtain a method with higher metrological quality, to characterize the CRMs for their contents of T-nos/hmg copy number ratio in maize. A duplex droplet digital PCR (ddPCR) assay was developed and optimized by a central composite design. The developed method achieved an absolute limit of detection (LOD) of 11 cP T-nos, a relative LOD of 0.034%, a limit of quantification (LOQ) of 23 cP (relative LOQ of 0.08%), and a dynamic range of 0.08%–100% T-nos/hmg ratio. The specificity and applicability of the assay were established for the analysis of low T-nos concentrations (0.9%) in several corn varieties. The convenience of DNA digestion to reduce measurement bias in the case of multiple-copy binding was confirmed through an enzymatic restriction assay. Given its overall performance, this method can be used to characterize CRM candidates for their contents of T-nos/hmg ratio. PMID:26605751
Massonneau, Agnes; Coronado, Maria-José; Audran, Arthur; Bagniewska, Agnieszka; Mòl, Rafal; Testillano, Pilar S; Goralski, Grzegorz; Dumas, Christian; Risueño, Maria-Carmen; Matthys-Rochon, Elisabeth
During maize pollen embryogenesis, a range of multicellular structures are formed. Using different approaches, the "nature" of these structures has been determined in terms of their embryogenic potential. In situ molecular identification techniques for gene transcripts and products, and a novel cell tracking system indicated the presence of embryogenic (embryo-like structures, ELS) and non-embryogenic (callus-like structures, CLS) structures that occurred for short periods within the cultures. Some multicellular structures with a compact appearance generated embryos. RT-PCR and fluorescence in situ hybridization (FISH) with confocal microscopy techniques using specific gene markers of the endosperm (ZmESR2, ZmAE3) and embryo (LTP2 and ZmOCL1, ZmOCL3) revealed "embryo" and "endosperm" potentialities in these various multicellular structures present in the cultures. The results presented here showed distinct and specific patterns of gene expression. Altogether, the results demonstrate the presence of different molecules on both embryonic and non-embryonic structures. Their possible roles are discussed in the context of a parallel between embryo/endosperm interactions in planta and embryonic and non-embryonic structure interrelations under in vitro conditions.
Zhu, Jiantang; Ding, Pengcheng; Li, Qingqing; Gao, YanKun; Chen, Fanguo; Xia, Guangmin
Methionine (Met) oxidation to methionine sulfoxide (MetSO) is a common form of damage caused by reactive oxygen species (ROS) accumulation via various environmental stresses. Methionine sulfoxide reductase (MSR) repairs oxidized Met and protects organisms from oxidative damage. Two types of MSR, A and B, have been identified based on substrate stereo specificity; they share no sequence similarity. In the present study, we characterized six genes encoding the putative MSR from two public databases. We compared them with MSRs from 6 species, and evaluated molecular characterization, phylogenetic analysis, tertiary structure and conserved motifs. On the basis of in silico and the qRT-PCR experimental data, we analyzed cDNA sequences and expression patterns of ZmMSR genes in different organs in maize. We found that ZmMSR genes were induced by polyethylene glycol (PEG) and NaCl, both known to generate oxidative stress. The results show that MSRs are conserved in different species, suggesting that MSRs across different species share common mechanisms related to diverse defense responses.
Anderson, M. D.; Prasad, T. K.; Martin, B. A.; Stewart, C. R.
An acclimation phenomenon was characterized in seedlings of chilling-sensitive maize (Zea mays L.) inbred G50 (Pioneer). Seedlings were germinated at 27[deg]C for 3 d and then exposed to chilling treatments of 4, 5, or 6[deg]C for 2, 4, 7, or 10 d in darkness. Damage symptoms in the more severe treatments included a waterlogged appearance and a discoloration of the tissue. The symptoms were most obvious in the mesocotyl. After a 10-d grow-out period in the greenhouse, moderately damaged seedlings exhibited chlorotic areas, an occasional disruption in leaf expansion, and a constriction of the mesocotyl. Growth and survival were improved by first exposing seedlings to a 14[deg]C acclimation treatment for 3 d before applying the chilling treatment. After chilling at 5[deg]C for 7 d, 79% of the acclimated seedlings survived, whereas only 22% of the nonacclimated seedlings survived. Differences in gene expression between acclimated and control seedlings were investigated using subtraction and differential screening techniques. Transcripts corresponding to three genes, car333, car30, and car757 (chilling acclimation responsive), were present in higher levels in seedlings after acclimation. Sequence analysis identified car333 as cat3, which encodes maize mitochondrial catalase isozyme 3. Characterization of these three clones revealed that all corresponding transcripts were elevated in acclimated seedlings in a manner that depended on the organ, i.e. coleoptile, mesocotyl, or root. Although transcripts were elevated in all three organs in response to acclimation, car30 was most abundant in the coleoptile and root, whereas cat3 and car757 were most abundant in the coleoptile and mesocotyl. Catalase activity followed the same general trend as cat3 transcript levels. Exogenous treatment with abscisic acid (ABA) resulted in an improvement in growth and survival of nonacclimated, chilled seedlings. Inhibition of ABA biosynthesis with fluridone abolished acclimation
Background The identification of QTL involved in heterosis formation is one approach to unravel the not yet fully understood genetic basis of heterosis - the improved agronomic performance of hybrid F1 plants compared to their inbred parents. The identification of candidate genes underlying a QTL is important both for developing markers and determining the molecular genetic basis of a trait, but remains difficult owing to the large number of genes often contained within individual QTL. To address this problem in heterosis analysis, we applied a meta-analysis strategy for grain yield (GY) of Zea mays L. as example, incorporating QTL-, hybrid field-, and parental gene expression data. Results For the identification of genes underlying known heterotic QTL, we made use of tight associations between gene expression pattern and the trait of interest, identified by correlation analyses. Using this approach genes strongly associated with heterosis for GY were discovered to be clustered in pericentromeric regions of the complex maize genome. This suggests that expression differences of sequences in recombination-suppressed regions are important in the establishment of heterosis for GY in F1 hybrids and also in the conservation of heterosis for GY across genotypes. Importantly functional analysis of heterosis-associated genes from these genomic regions revealed over-representation of a number of functional classes, identifying key processes contributing to heterosis for GY. Based on the finding that the majority of the analyzed heterosis-associated genes were addtitively expressed, we propose a model referring to the influence of cis-regulatory variation on heterosis for GY by the compensation of fixed detrimental expression levels in parents. Conclusions The study highlights the utility of a meta-analysis approach that integrates phenotypic and multi-level molecular data to unravel complex traits in plants. It provides prospects for the identification of genes relevant for
Zabala, G.; Gabay-Laughnan, S.; Laughnan, J. R.
The mitochondrial genomes of maize plants exhibiting S-type cytoplasmic male sterility (cms-S) contain a repeated DNA region designated R. This region was found to be rearranged in the mitochondria of all cms-S cytoplasmically revertant fertile plants in all nuclear backgrounds analyzed. A 1.6-kb mRNA transcribed from the R region in mitochondria of sterile plants was absent from all cytoplasmic revertants examined. The nuclear gene Rf3, which suppresses the cms-S phenotype, was found to have a specific effect on the expression of the R sequence; the abundance of the major R transcripts, including the cms-S-specific 1.6-kb mRNA, is decreased in mitochondria of restored plants. Nucleotide sequence analysis of R has revealed similarities to the R1 plasmid found in some South American maize races with RU cytoplasm, to the M1 plasmid found in one source of Zea luxurians teosinte, to the atp9 mitochondrial gene and its 3' flanking sequence, and also to a region 3' to the orf221 gene. The derived amino acid sequence of the R region predicts two open reading frames (ORFs). These ORFs contain the similarities to R1, M1, atp9 and orf221. The present report reveals the chimeric nature of the R region, describes the complex effect of Rf3 on the expression of the R sequence and implicates R in the sterile phenotype of cms-S maize. PMID:9335619
Vila, Laura; Quilis, Jordi; Meynard, Donaldo; Breitler, Jean Christophe; Marfà, Victoria; Murillo, Isabel; Vassal, Jean Michel; Messeguer, Joaquima; Guiderdoni, Emmanuel; San Segundo, Blanca
The maize proteinase inhibitor (mpi) gene was introduced into two elite japonica rice varieties. Both constitutive expression of the mpi gene driven by the maize ubiquitin 1 promoter and wound-inducible expression of the mpi gene driven by its own promoter resulted in the accumulation of MPI protein in the transgenic plants. No effect on plant phenotype was observed in mpi-expressing lines. The stability of transgene expression through successive generations of mpi rice lines (up to the T(4) generation) and the production of functional MPI protein were confirmed. Expression of the mpi gene in rice enhanced resistance to the striped stem borer (Chilo suppressalis), one of the most important pests of rice. In addition, transgenic mpi plants were evaluated in terms of their effects on the growth of C. suppressalis larvae and the insect digestive proteolytic system. An important dose-dependent reduction of larval weight of C. suppressalis larvae fed on mpi rice, compared with larvae fed on untransformed rice plants, was observed. Analysis of the digestive proteolytic activity from the gut of C. suppressalis demonstrated that larvae adapted to mpi transgene expression by increasing the complement of digestive proteolytic activity: the serine and cysteine endoproteinases as well as the exopeptidases leucine aminopeptidase and carboxypeptidases A and B. However, the induction of such proteolytic activity did not prevent the deleterious effects of MPI on larval growth. The introduction of the mpi gene into rice plants can thus be considered as a promising strategy to protect rice plants against striped stem borer.
Mortality of the western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae due to feeding on maize (Zea mays L.) expressing the eCry3.1Ab (5307), mCry3A (MIR604), and eCry3.1Ab + mCry3A proteins relative to survivorship on maize with the same genetic background without these genes (isoli...
Lu, Hai-Feng; Dong, Hai-Tao; Sun, Chang-Bin; Qing, Dong-Jin; Li, Ning; Wu, Zi-Kai; Wang, Zhi-Qiang; Li, You-Zhi
Changes in water potential, growth elongation, photosynthesis of three-leaf-old seedlings of maize inbred line YQ7-96 under water deficit (WD) for 0.5, 1 and 2 h and re-watering (RW) for 24 h were characterized. Gene expression was analyzed using cDNA microarray covering 11,855 maize unigenes. As for whole maize plant, the expression of WD-regulated genes was characterized by up-regulation. The expression of WD-regulated genes was categorized into eight different patterns, respectively, in leaves and roots. Newly found and WD-affected cellular processes were metabolic process, amino acid and derivative metabolic process and cell death. A great number of the analyzed genes were found to be regulated specifically by RW and commonly by both WD and RW, respectively, in leaves. It is therefore concluded that (1) whole maize plant tolerance to WD, as well as growth recovery from WD, depends at least in part on transcriptional coordination between leaves and roots; (2) WD exerts effects on the maize, especially on basal metabolism; (3) WD could probably affect CO(2) uptake and partitioning, and transport of fixed carbons; (4) WD could likely influence nuclear activity and genome stability; and (5) maize growth recovery from WD is likely involved in some specific signaling pathways related to RW-specific responsive genes.
Luan, Mingda; Xu, Miaoyun; Lu, Yunming; Zhang, Lan; Fan, Yunliu; Wang, Lei
The miR169 miRNA family is highly conserved in plants. Its members regulate the expression of genes encoding the universal transcription factor subunit NUCLEAR FACTOR-Y subunit A (NF-YA) via transcript cleavage. NF-YA regulates gene expression by binding the CCAAT box sequence in target promoters. The miR169/NF-YA module plays a critical role during plant development and in plant responses to abiotic stress. We characterized the secondary structures of maize pre-miR169 miRNAs and predicted their potential gene targets. Coexpression of zma-miR169 and ZmNF-YA in Nicotiana benthamiana demonstrated that mutations in or deletion of target sites abolished regulation by zma-miR169. Maize seedlings were subjected to short-term (0-48h) and long-term (15days) drought, abscisic acid (ABA), or salt stress. Long-term exposure to PEG (drought stress) or NaCl (salt stress) repressed seedling growth. We investigated the expression patterns of zma-miR169s and their target ZmNF-YA genes in maize leaves and found diverse changes in expression in response to the three stress treatments. The expression of most zma-miR169 genes was downregulated by PEG and upregulated by ABA. In response to salt stress, zma-miR169 genes were upregulated initially and subsequently downregulated. Most ZmNF-YA genes were upregulated during the short term and downregulated by 15days in response to the three stress treatments.
Li, Yajun; Wang, Meiling; Zhang, Fengxia; Xu, Yadong; Chen, Xiaohong; Qin, Xiaoliang; Wen, Xiaoxia
Glutamine synthetase (GS) and asparagine synthetase (AS) are proposed to have important function in plant nitrogen (N) remobilization, but their roles under drought stress are not well defined. In this study, the expression dynamics of GS and AS genes were analyzed in two maize varieties (ZD958 and NH101) in relation to post-silking drought stress induced nitrogen partitioning. ZD958 was a 'stay-green' variety with 5% nitrogen harvest index (NHI) lower than NH101. From silking to maturity, the amount of nitrogen remobilized from ear-leaves in ZD958 was evidently lower than NH101, and post-silking drought stress increased the nitrogen remobilization for both varieties. In ear-leaves, the expression of ZmGln1-3 was enhanced under drought stress. Three AS genes (ZmAS1, ZmAS2 and ZmAS3) were differentially regulated by post-silking drought treatment, of which the expression of ZmAS3 was stimulated at late stage of leaf senescence. In NH101, the expression level of ZmAS3 was markedly higher than that in ZD958. In developing grains, there were no significant differences in expression patterns of GS and AS genes between well water and drought treated plants. Drought stress altered maize N partitioning at the whole-plant level, and the up-regulation of GS and AS genes may contribute to the higher leaf nitrogen remobilization when exposed to drought treatments.
Selinger, D A; Lisch, D; Chandler, V L
The B-Peru allele of the maize b regulatory gene is unusual relative to most b alleles in that it is expressed in the aleurone layer of the seed. It is also expressed in a subset of plant vegetative tissues. Transgenic maize plants containing the B-Peru gene with the first 710 bases of upstream sequence conferred the same levels of aleurone expression as nontransgenic B-Peru plants, but no pigment was made in vegetative tissues. Transient transformation assays in aleurone tissue localized the aleurone-specific promoter to the first 176 bases of the B-Peru upstream region and identified two critically important regions within this fragment. Mutation of either region alone reduced expression greater than fivefold. Surprisingly, the double mutation actually increased expression to twice the native promoter level. Our results suggest that these two critical sequences, which lie close together in the promoter, may form a negative regulatory element. Several lines of evidence suggest that the B-Peru promoter arose through the translocation of an existing aleurone-specific promoter to the b locus. Immediately upstream of the aleurone-specific promoter elements and in the opposite orientation to the b coding sequence is a pseudogene sequence with strong similarity to a known class of proteins. Our findings that novel aleurone-specific promoter sequences of the B-Peru transcription factor are found adjacent to part of another gene in a small insertion are quite unexpected and have interesting evolutionary implications. PMID:9611220
Gresset, Sebastian; Westermeier, Peter; Rademacher, Svenja; Ouzunova, Milena; Presterl, Thomas; Westhoff, Peter; Schön, Chris-Carolin
In plants with C4 photosynthesis, physiological mechanisms underlying variation in stable carbon isotope discrimination (Δ13C) are largely unknown, and genetic components influencing Δ13C have not been described. We analyzed a maize (Zea mays) introgression library derived from two elite parents to investigate whether Δ13C is under genetic control in this C4 species. High-density genotyping with the Illumina MaizeSNP50 Bead Chip was used for a detailed structural characterization of 89 introgression lines. Phenotypic analyses were conducted in the field and in the greenhouse for kernel Δ13C as well as plant developmental and photosynthesis-related traits. Highly heritable significant genetic variation for Δ13C was detected under field and greenhouse conditions. For several introgression library lines, Δ13C values consistently differed from the recurrent parent within and across the two phenotyping platforms. Δ13C was significantly associated with 22 out of 164 analyzed genomic regions, indicating a complex genetic architecture of Δ13C. The five genomic regions with the largest effects were located on chromosomes 1, 2, 6, 7, and 9 and explained 55% of the phenotypic variation for Δ13C. Plant development stage had no effect on Δ13C expression, as phenotypic as well as genotypic correlations between Δ13C, flowering time, and plant height were not significant. To our knowledge, this is the first study demonstrating Δ13C to be under polygenic control in the C4 species maize. PMID:24280436
Ernst, Laura; Goodger, Jason Q D; Alvarez, Sophie; Marsh, Ellen L; Berla, Bert; Lockhart, Eric; Jung, Jiyul; Li, Pinghua; Bohnert, Hans J; Schachtman, Daniel P
Recent reports suggest that early sensing of soil water stress by plant roots and the concomitant reduction in stomatal conductance may not be mediated by root-sourced abscisic acid (ABA), but that other xylem-borne chemicals may be the primary stress signal(s). To gain more insight into the role of root-sourced ABA, the timing and location of the expression of genes for key enzymes involved in ABA biosynthesis in Zea mays roots was measured and a comprehensive analysis of root xylem sap constituents from the early to the later stages of water stress was conducted. Xylem sap and roots were sampled from plants at an early stage of water stress when only a reduction in leaf conductance was measured, as well as at later stages when leaf xylem pressure potential decreased. It was found that the majority of ABA biosynthetic genes examined were only significantly expressed in the elongation region of roots at a later stage of water stress. Apart from ABA, sulphate was the only xylem-borne chemical that consistently showed significantly higher concentrations from the early to the later stages of stress. Moreover, there was an interactive effect of ABA and sulphate in decreasing maize transpiration rate and Vicia faba stomatal aperture, as compared to ABA alone. The expression of a sulphate transporter gene was also analysed and it was found that it had increased in the elongation region of roots from the early to the later stages of water stress. Our results support the suggestion that in the early stage of water stress, increased levels of ABA in xylem sap may not be due to root biosynthesis, ABA glucose ester catabolism or pH-mediated redistribution, but may be due to shoot biosynthesis and translocation to the roots. The analysis of xylem sap mineral content and bioassays indicate that the anti-transpirant effect of the ABA reaching the stomata at the early stages of water stress may be enhanced by the increased concentrations of sulphate in the xylem which is also
The gene encoding lycotoxin I, an amphipathic pore-forming peptide, was modified to increase oral toxicity to insects. One of the most active modified genes was then constitutively expressed in tobacco (Nicotiana tabacum) and transformants were evaluated for insect and disease resistance. Pathogenic...
Wonder, John P.
Elaborates on and updates the article "Derived Noun Phrases in Spanish Containing Locatives" by John P. Wonder and Alberto Eraso Guerrero (1976). Gives a detailed description of the uses of "ser" and "haber" in the locative expression. (NCR)
Peng, Shanli; Xue, Lei; Leng, Xue; Yang, Ruobing; Zhang, Genyi; Hamaker, Bruce R
The in vivo slow digestion property of octenyl succinic anhydride modified waxy corn starch (OSA-starch) in the presence of tea polyphenols (TPLs) was studied. Using a mouse model, the experimental results showed an extended and moderate postprandial glycemic response with a delayed and significantly decreased blood glucose peak of OSA-starch after cocooking with TPLs (5% starch weight base). Further studies revealed an increased hydrodynamic radius of OSA-starch molecules indicating an interaction between OSA-starch and TPLs. Additionally, decreased gelatinization temperature and enthalpy and reduced viscosity and emulsifiability of OSA-starch support their possible complexation to form a spherical OSA-starch-TPLs (OSAT) complex. The moderate and extended postprandial glycemic response is likely caused by decreased activity of mucosal α-glucosidase, which is noncompetitively inhibited by tea catechins released from the complex during digestion. Meanwhile, a significant decrease of malondialdehyde (MDA) and increased DPPH free radical scavenging activity in small intestine tissue demonstrated the antioxidative functional property of the OSAT complex. Thus, the complex of OSAT, acting as a functional carbohydrate material, not only leads to a flattened and prolonged glycemic response but also reduces the oxidative stress, which might be beneficial to health.
Sénéchal, Fabien; Wattier, Christopher; Rustérucci, Christine; Pelloux, Jérôme
Understanding the changes affecting the plant cell wall is a key element in addressing its functional role in plant growth and in the response to stress. Pectins, which are the main constituents of the primary cell wall in dicot species, play a central role in the control of cellular adhesion and thereby of the rheological properties of the wall. This is likely to be a major determinant of plant growth. How the discrete changes in pectin structure are mediated is thus a key issue in our understanding of plant development and plant responses to changes in the environment. In particular, understanding the remodelling of homogalacturonan (HG), the most abundant pectic polymer, by specific enzymes is a current challenge in addressing its fundamental role. HG, a polymer that can be methylesterified or acetylated, can be modified by HGMEs (HG-modifying enzymes) which all belong to large multigenic families in all species sequenced to date. In particular, both the degrees of substitution (methylesterification and/or acetylation) and polymerization can be controlled by specific enzymes such as pectin methylesterases (PMEs), pectin acetylesterases (PAEs), polygalacturonases (PGs), or pectate lyases-like (PLLs). Major advances in the biochemical and functional characterization of these enzymes have been made over the last 10 years. This review aims to provide a comprehensive, up to date summary of the recent data concerning the structure, regulation, and function of these fascinating enzymes in plant development and in response to biotic stresses. PMID:25056773
Séralini, Gilles-Eric; Cellier, Dominique; de Vendomois, Joël Spiroux
Health risk assessment of genetically modified organisms (GMOs) cultivated for food or feed is under debate throughout the world, and very little data have been published on mid- or long-term toxicological studies with mammals. One of these studies performed under the responsibility of Monsanto Company with a transgenic corn MON863 has been subjected to questions from regulatory reviewers in Europe, where it was finally approved in 2005. This necessitated a new assessment of kidney pathological findings, and the results remained controversial. An Appeal Court action in Germany (Münster) allowed public access in June 2005 to all the crude data from this 90-day rat-feeding study. We independently re-analyzed these data. Appropriate statistics were added, such as a multivariate analysis of the growth curves, and for biochemical parameters comparisons between GMO-treated rats and the controls fed with an equivalent normal diet, and separately with six reference diets with different compositions. We observed that after the consumption of MON863, rats showed slight but dose-related significant variations in growth for both sexes, resulting in 3.3% decrease in weight for males and 3.7% increase for females. Chemistry measurements reveal signs of hepatorenal toxicity, marked also by differential sensitivities in males and females. Triglycerides increased by 24-40% in females (either at week 14, dose 11% or at week 5, dose 33%, respectively); urine phosphorus and sodium excretions diminished in males by 31-35% (week 14, dose 33%) for the most important results significantly linked to the treatment in comparison to seven diets tested. Longer experiments are essential in order to indicate the real nature and extent of the possible pathology; with the present data it cannot be concluded that GM corn MON863 is a safe product.
Décima Oneto, Cecilia; Otegui, María Elena; Baroli, Irene; Beznec, Ailin; Faccio, Paula; Bossio, Ezequiel; Blumwald, Eduardo; Lewi, Dalia
Senescence can be delayed in transgenic plants overexpressing the enzyme isopentenyltransferase (IPT) due to stress-induced increased levels of endogenous cytokinins. This trait leads to sustained photosynthetic activity and improved tolerance to abiotic stress. The aim of this study was to generate and characterize transgenic plants of maize (Zea mays L.) transformed with the IPT gene sequence under the regulation of SARK promoter (protein kinase receptor-associated senescence). Three independent transgenic events and their segregating null controls were evaluated in two watering regimes (WW: well watered; WD: water deficit) imposed for two weeks around anthesis. Our results show that the WD treatment induced IPT expression with the concomitant increase in cytokinin levels, which prolonged the persistence of total green leaf area, and maintained normal photosynthetic rate and stomatal conductance. These trends were accompanied by a minor decrease in number of grains per plant, individual grain weight and plant grain yield as compared to WW plants. Plants expressing the IPT gene under WD had PGR, anthesis and silking dates and biomass levels similar to WW plants. Our results demonstrate that expression of the IPT gene under the regulation of the SARK promoter helps improve productivity under WD conditions in C4 plants like maize.
Universal primer-multiplex-polymerase chain reaction (UP-M-PCR) and capillary electrophoresis-laser-induced fluorescence analysis for the simultaneous detection of six genetically modified maize lines.
Zhang, Chunjiao; Xu, Wentao; Zhai, Zhifang; Luo, Yunbo; Yan, Xinghua; Zhang, Nan; Huang, Kunlun
To meet the labeling and traceability requirement of genetically modified (GM) maize and their products for trade and regulation, it is essential to develop a specific detection method for monitoring the presence of GM content. In this work, six GM maize lines, including GA21, Bt11, NK603, Bt176, Mir604, and Mon810, were simultaneously detected by universal primer-multiplex-polymerase chain reaction (UP-M-PCR), and the amplicons for the six event-specific genes as well as the endogenous Ivr gene were successfully separated by the method of capillary electrophoresis-laser-induced fluorescence (CE-LIF). The UP-M-PCR method overcame the disadvantages in conventional M-PCR, such as complex manipulation, lower sensitivity, amplification disparity resulting from different primers, etc., and in combination with CE-LIF, it obtained a high sensitivity of 0.1 ng for both single and mixed DNA samples. The established method can be widely used for the qualitative identification of the GM maize lines.
Heredia Díaz, Oscar; Aldaba Meza, José Luis; Baltazar, Baltazar M; Bojórquez Bojórquez, Germán; Castro Espinoza, Luciano; Corrales Madrid, José Luis; de la Fuente Martínez, Juan Manuel; Durán Pompa, Héctor Abel; Alonso Escobedo, José; Espinoza Banda, Armando; Garzón Tiznado, José Antonio; González García, Juvencio; Guzmán Rodríguez, José Luis; Madueño Martínez, Jesús Ignacio; Martínez Carrillo, José Luis; Meng, Chen; Quiñones Pando, Francisco Javier; Rosales Robles, Enrique; Ruiz Hernández, Ignacio; Treviño Ramírez, José Elías; Uribe Montes, Hugo Raúl; Zavala García, Francisco
Environmental risk assessment (ERA) of genetically modified (GM) crops is a process to evaluate whether the biotechnology trait(s) in a GM crop may result in increased pest potential or harm to the environment. In this analysis, two GM insect-resistant (IR) herbicide-tolerant maize hybrids (MON-89Ø34-3 × MON-88Ø17-3 and MON-89Ø34-3 × MON-ØØ6Ø3-6) and one herbicide-tolerant GM hybrid (MON-ØØ6Ø3-6) were compared with conventional maize hybrids of similar genetic backgrounds. Two sets of studies, Experimental Phase and Pilot Phase, were conducted across five ecological regions (ecoregions) in Mexico during 2009-2013, and data were subject to meta-analysis. Results from the Experimental Phase studies, which were used for ERA, indicated that the three GM hybrids were not different from conventional maize for early stand count, days-to-silking, days-to-anthesis, root lodging, stalk lodging, or final stand count. Statistically significant differences were observed for seedling vigor, ear height, plant height, grain moisture, and grain yield, particularly in the IR hybrids; however, none of these phenotypic differences are expected to contribute to a biological or ecological change that would result in an increased pest potential or ecological risk when cultivating these GM hybrids. Overall, results from the Experimental Phase studies are consistent with those from other world regions, confirming that there are no additional risks compared to conventional maize. Results from Pilot Phase studies indicated that, compared to conventional maize hybrids, no differences were detected for the agronomic and phenotypic characteristics measured on the three GM maize hybrids, with the exception of grain moisture and grain yield in the IR hybrids. Since MON-89Ø34-3 × MON-88Ø17-3 and MON-89Ø34-3 × MON-ØØ6Ø3-6 confer resistance to target insect pests, they are an alternative for farmers in Mexico to protect the crop from insect damage. Additionally, the
Cohen, Daniel J.; Morfino, Roberto C.; Maharbiz, Michel M.
This paper presents a low-cost inkjet dosing system capable of continuous, two-dimensional spatiotemporal regulation of gene expression via delivery of diffusible regulators to a custom-mounted gel culture of E. coli. A consumer-grade, inkjet printer was adapted for chemical printing; E. coli cultures were grown on 750 µm thick agar embedded in micro-wells machined into commercial compact discs. Spatio-temporal regulation of the lac operon was demonstrated via the printing of patterns of lactose and glucose directly into the cultures; X-Gal blue patterns were used for visual feedback. We demonstrate how the bistable nature of the lac operon's feedback, when perturbed by patterning lactose (inducer) and glucose (inhibitor), can lead to coordination of cell expression patterns across a field in ways that mimic motifs seen in developmental biology. Examples of this include sharp boundaries and the generation of traveling waves of mRNA expression. To our knowledge, this is the first demonstration of reaction-diffusion effects in the well-studied lac operon. A finite element reaction-diffusion model of the lac operon is also presented which predicts pattern formation with good fidelity. PMID:19763256
Development of multicellular organisms proceeds via the correct interpretation of positional information to establish boundaries that separate developmental fields with distinct identities. The maize (Zea mays) leaf is an ideal system to study plant morphogenesis as it is subdivided into a proximal ...
Maize (Zea mays) leaves provide a useful system to study how proximal/distal patterning is established because of the distinct tissues found in the distal blade and the proximal sheath. Several mutants disrupt this pattern, including the dominant knotted1-like homeobox (knox) mutants. knox genes enc...
Modern maize breeding and selection for large starchy kernels may have contributed to reduced contents of essential amino acids which represents a serious nutritional problem for humans and animals. The improvement of low levels of essential amino acids, while maintaining high protein content and ha...
Aspergillus niger and A. carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspe...
Tolley, Ben J.; Sage, Tammy L.; Langdale, Jane A.; Hibberd, Julian M.
C4 photosynthesis has evolved in at least 66 lineages within the angiosperms and involves alterations to the biochemistry, cell biology, and development of leaves. The characteristic “Kranz” anatomy of most C4 leaves was discovered in the 1890s, but the genetic basis of these traits remains poorly defined. Oat × maize addition lines allow the effects of individual maize (Zea mays; C4) chromosomes to be investigated in an oat (Avena sativa; C3) genetic background. Here, we have determined the extent to which maize chromosomes can introduce C4 characteristics into oat and have associated any C4-like changes with specific maize chromosomes. While there is no indication of a simultaneous change to C4 biochemistry, leaf anatomy, and ultrastructure in any of the oat × maize addition lines, the C3 oat leaf can be modified at multiple levels. Maize genes encoding phosphoenolpyruvate carboxylase, pyruvate, orthophosphate dikinase, and the 2′-oxoglutarate/malate transporter are expressed in oat and generate transcripts of the correct size. Three maize chromosomes independently cause increases in vein density, and maize chromosome 3 results in larger bundle sheath cells with increased cell wall lipid deposition in oat leaves. These data provide proof of principle that aspects of C4 biology could be integrated into leaves of C3 crops. PMID:22675083
Gómez, Elisa; Royo, Joaquín; Guo, Yan; Thompson, Richard; Hueros, Gregorio
In maize, cells at the base of the endosperm are transformed into transfer cells that facilitate nutrient uptake by the developing seed. ZmMRP-1 is the first transfer cell-specific transcriptional activator to be identified. The protein it encodes contains nuclear localization signals and a MYB-related DNA binding domain. A single gene copy is present in maize, mapping to a locus on chromosome 8. ZmMRP-1 is first expressed soon after fertilization, when the endosperm is still a multinuclear coenocyte. The transcript accumulates in the basal nucleocytoplasmic domain that gives rise to transfer cells after cellularization. The transcript can be detected throughout transfer cell development, but it is not found in mature cells. ZmMRP-1 strongly transactivates the promoters of two unrelated transfer cell-specific genes. The properties of ZmMRP-1 are consistent with it being a determinant of transfer cell-specific expression. Possible roles for ZmMRP-1 in the regulation of endosperm and transfer cell differentiation are discussed.
Mattei, Vincenzo; Martellucci, Stefano; Santilli, Francesca; Manganelli, Valeria; Garofalo, Tina; Candelise, Niccolò; Caruso, Alessandra; Sorice, Maurizio; Scaccianoce, Sergio
The hippocampus is a vulnerable brain structure susceptible to damage during aging and chronic stress. Repeated exposure to opioids may alter the brain so that it functions normally when the drugs are present, thus, a prolonged withdrawal might lead to homeostatic changes headed for the restoration of the physiological state. Abuse of morphine may lead to Reacting Oxygen Species-induced neurodegeneration and apoptosis. It has been proposed that during morphine withdrawal, stress responses might be responsible, at least in part, for long-term changes of hippocampal plasticity. Since prion protein is involved in both, Reacting Oxygen Species mediated stress responses and synaptic plasticity, in this work we investigate the effect of opiate withdrawal in rats after morphine treatment. We hypothesize that stressful stimuli induced by opiate withdrawal, and the subsequent long-term homeostatic changes in hippocampal plasticity, might modulate the Prion protein expression. Our results indicate that abstinence from the opiate induced a time-dependent and region-specific modification in Prion protein content, indeed during morphine withdrawal a selective unbalance of hippocampal Prion Protein is observable. Moreover, Prion protein overexpression in hippocampal tissue seems to generate a dimeric structure of Prion protein and α-cleavage at the hydrophobic domain. Stress factors or toxic insults can induce cytosolic dimerization of Prion Protein through the hydrophobic domain, which in turn, it stimulates the α-cleavage and the production of neuroprotective Prion protein fragments. We speculate that this might be the mechanism by which stressful stimuli induced by opiate withdrawal and the subsequent long-term homeostatic changes in hippocampal plasticity, modulate the expression and the dynamics of Prion protein. PMID:28081197
Scholtz, N D; Halle, I; Dänicke, S; Hartmann, G; Zur, B; Sauerwein, H
Potentially adverse effects of diets containing transgenic plants are a concern for many consumers, particularly in Europe. For Bacillus thuringiensis-maize, several studies in livestock and poultry showed that the zootechnical data provide no indication for such adverse effects. These studies were all done in homeostatic situations; it remained open whether a deflection of the regulatory physiological systems might yield divergent dynamic responses in B. thuringiensis-maize-fed animals. We therefore tested the effect of an active immunization using BSA as antigen in a feeding regimen with or without B. thuringiensis-maize using quail as a model organism. Newly hatched Japanese quail were randomly allocated to 2 groups (n=120 per group) fed with diets containing either B. thuringiensis-maize or isogenic maize of the same cultivar. The diets did not differ in concentrations of the mycotoxins deoxynivalenol and zearalenone, which were both far below guidance values. After 16 wk on the experimental diets, one-half of each group was immunized against BSA. The remaining birds were injected with saline. Thirty-six hours after the injection, half of the BSA-injected subgroup (n=30) and half of the saline subgroup (n=30) from B. thuringiensis-maize- and isogenic-fed birds were killed and blood samples were collected and analyzed for serum zinc levels, indicative for acute phase response. For determining IgY-mediated immune responses, eggs were collected every other week for 6 wk after the injections from the remaining birds and total IgY concentrations and BSA-specific IgY titers were measured in egg yolk. The BSA injections did not elicit significant decreases of serum zinc concentrations. The serum zinc levels were significantly higher in B. thuringiensis-maize-fed quail. Expectedly, total IgY as well as BSA-specific IgY titers increased with time in the BSA-immunized quail. The response of both variables to the BSA injection did not differ between the feeding groups
Gullì, Mariolina; Salvatori, Elisabetta; Fusaro, Lina; Pellacani, Claudia; Manes, Fausto; Marmiroli, Nelson
Maize MON810, grown and commercialised worldwide, is the only cultivated GM event in the EU. Maize MON810, variety DKC6575, and the corresponding near-isogenic line Tietar were studied in different growth conditions, to compare their behaviour in response to drought. Main photosynthetic parameters were significantly affected by drought stress in both GM and non-GM varieties to a similar extent. Though DKC6575 (GM) had a greater sensitivity in the early phase of stress response as compared with Tietar (non-GM), after six days of stress they behaved similarly, and both varieties recovered from stress damage. Profiling gene expression in water deficit regimes and in a generalised drought stress condition showed an up-regulation of many stress-responsive genes, but a greater number of differentially expressed genes was observed in Tietar, with genes belonging to transcription factor families and genes encoding heat shock proteins, late embryogenesis abundant proteins and detoxification enzymes. Since induction of these genes have been indicated from the literature as typical of stress responses, their activation in Tietar rather than in DKC6575 may be reminiscent of a more efficient response to drought. DKC6575 was also analysed for the expression of the transgene CryIAb (encoding the delta-endotoxin insecticidal protein) in water deficit conditions. In all the experiments, the CryIAb transcript was not influenced by drought stress, but was expressed at a constant level. This suggests that though possessing a different pattern of sensitivity to stress, the GM variety maintains the same expression level for the transgene. PMID:25692547
Dhar, A.; Ganguly, P.
Platelets are anucleated cells which play an important part in blood coagulation and thrombosis. These cells may be stored in the blood bank for only 4/5 days. In order to improve the storage of platelets, it is essential to first understand the changes in these cells due to storage. In this work, human platelets were stored in autologous plasma at 4/sup 0/ or 22/sup 0/ and their surface changes were monitored with three lectins - wheat germ afflutinin (WGA), concanavalin A (Con A) and lentil lectin (LL). Blood was drawn from healthy donors and platelet rich plasma (PRP) was collected by slow speed centrifugation. Platelets stored at either temperature for different times showed increased sensitivity to agglutination by WGA after 34-48 hrs. Lectins, Con A and LL, which were not agglutinating to fresh platelets readily caused agglutination after 48-72 hrs. The platelets stored for 25 hrs or longer period were insensitive to thrombin but showed enhanced aggregation with WGA. Labelling of surface glycoconjugates of stored platelets with /sup 3/H-boro-hydride revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb infinity) together with the appearance of components of Mr 69,000; Mr 60,000; Mr 25,000. New high molecular weight glycoproteins were also detected only in stored platelets. The author studies clearly indicate that modification or altered expression of platelets surface glycoproteins may be one factor of storage related dysfunction of platelets.
Sun, Hyeon-Jin; Cui, Min-Long; Ma, Biao; Ezura, Hiroshi
Taste-modifying proteins are a natural alternative to artificial sweeteners and flavor enhancers and have been used in some cultures for centuries. The taste-modifying protein, miraculin, has the unusual property of being able to modify a sour taste into a sweet taste. Here, we report the use of a plant expression system for the production of miraculin. A synthetic gene encoding miraculin was placed under the control of constitutive promoters and transferred to lettuce. Expression of this gene in transgenic lettuce resulted in the accumulation of significant amounts of miraculin protein in the leaves. The miraculin expressed in transgenic lettuce possessed sweetness-inducing activity. These results demonstrate that the production of miraculin in edible plants can be a good alternative strategy to enhance the availability of this protein.
Amylomaize VII, a class of High Amylose Maize with at least 70% of the kernel starch composed of the linear amylose polymer, has had numerous food and industrial applications including the manufacturing of biodegradable plastics, adhesives and candies. More recently it has been found to be a signi...
Oguchi, Taichi; Onishi, Mari; Mano, Junichi; Akiyama, Hiroshi; Teshima, Reiko; Futo, Satoshi; Furui, Satoshi; Kitta, Kazumi
A novel multiplex PCR method was developed for simultaneous event-specific detection of four events of GM maize, i.e., DAS-59122-7, MIR604, MON88017, and MON863. The single laboratory examination of analytical performance using simulated DNA mixtures containing GM DNA at various concentrations in non-GM DNA suggested that the limits of detection (LOD) of the multiplex PCR method were 0.16% for MON863, MIR604, and MON88017, and 0.078% for DAS-59122-7. We previously developed a nonaplex (9plex) PCR method for eight events of GM maize, i.e., Bt11, Bt176, GA21, MON810, MON863, NK603, T25, and TC1507. Together with the nonaplex PCR method, the newly developed method enabled the detection and identification of eleven GM maize events that are frequently included in commercial GM seed used in Japan. In addition, this combinational analysis may be useful for the identification of combined event products of GM maize.
Shen, Bo; Allen, William B; Zheng, Peizhong; Li, Changjiang; Glassman, Kimberly; Ranch, Jerry; Nubel, Douglas; Tarczynski, Mitchell C
Increasing seed oil production is a major goal for global agriculture to meet the strong demand for oil consumption by humans and for biodiesel production. Previous studies to increase oil synthesis in plants have focused mainly on manipulation of oil pathway genes. As an alternative to single-enzyme approaches, transcription factors provide an attractive solution for altering complex traits, with the caveat that transcription factors may face the challenge of undesirable pleiotropic effects. Here, we report that overexpression of maize (Zea mays) LEAFY COTYLEDON1 (ZmLEC1) increases seed oil by as much as 48% but reduces seed germination and leaf growth in maize. To uncouple oil increase from the undesirable agronomic traits, we identified a LEC1 downstream transcription factor, maize WRINKLED1 (ZmWRI1). Overexpression of ZmWRI1 results in an oil increase similar to overexpression of ZmLEC1 without affecting germination, seedling growth, or grain yield. These results emphasize the importance of field testing for developing a commercial high-oil product and highlight ZmWRI1 as a promising target for increasing oil production in crops.
Palmer, Lance E; Rabinowicz, Pablo D; O'Shaughnessy, Andrew L; Balija, Vivekanand S; Nascimento, Lidia U; Dike, Sujit; de la Bastide, Melissa; Martienssen, Robert A; McCombie, W Richard
Gene enrichment strategies offer an alternative to sequencing large and repetitive genomes such as that of maize. We report the generation and analysis of nearly 100,000 undermethylated (or methylation filtration) maize sequences. Comparison with the rice genome reveals that methylation filtration results in a more comprehensive representation of maize genes than those that result from expressed sequence tags or transposon insertion sites sequences. About 7% of the repetitive DNA is unmethylated and thus selected in our libraries, but potentially active transposons and unmethylated organelle genomes can be identified. Reverse transcription polymerase chain reaction can be used to finish the maize transcriptome.
van Leeuwen, F; Wijsman, E R; Kieft, R; van der Marel, G A; van Boom, J H; Borst, P
African trypanosomes such as Trypanosoma brucei undergo antigenic variation in the bloodstream of their mammalian hosts by regularly changing the variant surface glycoprotein (VSG) gene expressed. The transcribed VSG gene is invariably located in a telomeric expression site. There are multiple expression sites and one way to change the VSG gene expressed is by activating a new site and inactivating the previously active one. The mechanisms that control expression site switching are unknown, but have been suggested to involve epigenetic regulation. We have found previously that VSG genes in silent (but not active) expression sites contain modified restriction endonuclease cleavage sites, and we have presented circumstantial evidence indicating that this is attributable to the presence of a novel modified base beta-D-glucosyl-hydroxymethyluracil, or J. To directly test this, we have generated antisera that specifically recognize J-containing DNA and have used these to determine the precise location of this modified thymine in the telomeric VSG expression sites. By anti J-DNA immunoprecipitations, we found that J is present in telomeric VSG genes in silenced expression sites and not in actively transcribed telomeric VSG genes. J was absent from inactive chromosome-internal VSG genes. DNA modification was also found at the boundaries of expression sites. In the long 50-bp repeat arrays upstream of the promoter and in the telomeric repeat arrays downstream of the VSG gene, J was found both in silent and active expression sites. This suggests that silencing results in a gradient of modification spreading from repetitive DNA flanks into the neighboring expression site sequences. In this paper, we discuss the possible role of J in silencing of expression sites.
The Maize Database (MaizeDB) to the Maize Genetics and Genomics Database (MaizeGDB) turns 20 this year, and such a significant milestone must be celebrated! With the release of the B73 reference sequence and more sequenced genomes on the way, the maize community needs to address various opportunitie...
Fornwald, James A; Lu, Quinn; Boyce, Frederick M; Ames, Robert S
BacMams are modified baculoviruses that contain mammalian expression cassettes for gene delivery and expression in mammalian cells. BacMams have become an integral part of the recombinant mammalian gene expression toolbox in research labs worldwide. Construction of transfer vectors is straightforward using basic molecular biology protocols. Virus generation is based on common methods used with the baculovirus insect cell expression system. BacMam transduction of mammalian cells requires minimal modifications to familiar cell culture methods. This chapter highlights the BacMam transfer vector pHTBV.
Murata, Hideki; Yoshimoto, Koji; Hatae, Ryusuke; Akagi, Yojiro; Mizoguchi, Masahiro; Hata, Nobuhiro; Kuga, Daisuke; Nakamizo, Akira; Amano, Toshiyuki; Sayama, Tetsuro; Iihara, Koji
Proneural and mesenchymal are two subtypes of glioblastoma identified by gene expression profiling. In this study, the primary aim was to detect markers to develop a clinically applicable method for distinguishing proneural and mesenchymal glioblastoma. The secondary aims were to investigate the temporospatial dynamics of these markers and to explore the association between these markers and the expression of chromatin-modifying genes. One hundred thirty-three glioma samples (grade II: 14 samples, grade III: 18, grade IV: 101) were analyzed. We quantified the expression of 6 signature genes associated with proneural and mesenchymal glioblastoma by quantitative reverse transcription-polymerase chain reaction. We assigned proneural (PN) and mesenchymal (MES) scores based on the average of the 6 markers and calculated a predominant metagene (P-M) score by subtracting the MES from the PN score. We used these scores to analyze correlations with malignant transformation, tumor recurrence, tumor heterogeneity, chromatin-modifying gene expression, and HDAC7 expression. The MES score positively correlated with tumor grade, whereas the PN score did not. The P-M score was able to distinguish the proneural and mesenchymal subtypes. It was decreased in cases of tumor recurrence and malignant transformation and showed variability within a tumor, suggesting intratumoral heterogeneity. The PN score correlated with the expression of multiple histone-modifying genes, whereas the MES score was associated only with HDAC7 expression. Thus, we demonstrated a simple and straightforward method of quantifying proneural/mesenchymal markers in glioblastoma. Of note, HDAC7 expression might be a novel therapeutic target in glioblastoma treatment.
Härtel, Stephan; Näther, Astrid; Dohrmann, Anja B.; Steffan-Dewenter, Ingolf; Tebbe, Christoph C.
Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees. PMID:23533634
Hendriksma, Harmen P; Küting, Meike; Härtel, Stephan; Näther, Astrid; Dohrmann, Anja B; Steffan-Dewenter, Ingolf; Tebbe, Christoph C
Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.
Pyramiding expression of maize genes encoding phosphoenolpyruvate carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) synergistically improve the photosynthetic characteristics of transgenic wheat.
Zhang, HuiFang; Xu, WeiGang; Wang, HuiWei; Hu, Lin; Li, Yan; Qi, XueLi; Zhang, Lei; Li, ChunXin; Hua, Xia
Using particle bombardment transformation, we introduced maize pepc cDNA encoding phosphoenolpyruvate carboxylase (PEPC) and ppdk cDNA encoding pyruvate orthophosphate dikinase (PPDK) into the C3 crop wheat to generate transgenic wheat lines carrying cDNA of pepc (PC lines), ppdk (PK lines) or both (PKC lines). The integration, transcription, and expression of the foreign genes were confirmed by Southern blot, Real-time quantitative reverse transcription PCR (Q-RT-PCR), and Western blot analysis. Q-RT-PCR results indicated that the average relative expression levels of pepc and ppdk in the PKC lines reached 10 and 4.6, respectively, compared to their expressions in untransformed plants (set to 1). The enzyme activities of PEPC and PPDK in the PKC lines were 4.3- and 2.1-fold higher, respectively, than in the untransformed control. The maximum daily net photosynthetic rates of the PKC, PC, and PK lines were enhanced by 26.4, 13.3, and 4.5%, respectively, whereas the diurnal accumulations of photosynthesis were 21.3, 13.9, and 6.9%, respectively, higher than in the control. The Fv/Fm of the transgenic plants decreased less than in the control under high temperature and high light conditions (2 weeks after anthesis), suggesting that the transgenic wheat transports more absorbed light energy into a photochemical reaction. The exogenous maize C4-specific pepc gene was more effective than ppdk at improving the photosynthetic performance and yield characteristics of transgenic wheat, while the two genes showed a synergistic effect when they were transformed into the same genetic background, because the PKC lines exhibited improved photosynthetic and physiological traits.
Bodnar, Anastasia L; Proulx, Amy K; Scott, M Paul; Beavers, Alyssa; Reddy, Manju B
Maize ( Zea mays ) is an important staple crop in many parts of the world but has low iron bioavailability, in part due to its high phytate content. Hemoglobin is a form of iron that is highly bioavailable, and its bioavailability is not inhibited by phytate. It was hypothesized that maize hemoglobin is a highly bioavailable iron source and that biofortification of maize with iron can be accomplished by overexpression of maize globin in the endosperm. Maize was transformed with a gene construct encoding a translational fusion of maize globin and green fluorescent protein under transcriptional control of the maize 27 kDa γ-zein promoter. Iron bioavailability of maize hemoglobin produced in Escherichia coli and of stably transformed seeds expressing the maize globin-GFP fusion was determined using an in vitro Caco-2 cell culture model. Maize flour fortified with maize hemoglobin was found to have iron bioavailability that is not significantly different from that of flour fortified with ferrous sulfate or bovine hemoglobin but is significantly higher than unfortified flour. Transformed maize grain expressing maize globin was found to have iron bioavailability similar to that of untransformed seeds. These results suggest that maize globin produced in E. coli may be an effective iron fortificant, but overexpressing maize globin in maize endosperm may require a different strategy to increase bioavailable iron content in maize.
NAGAYA, Masaki; WATANABE, Masahito; KOBAYASHI, Mirina; NAKANO, Kazuaki; ARAI, Yoshikazu; ASANO, Yoshinori; TAKEISHI, Toki; UMEKI, Ikuma; FUKUDA, Tooru; YASHIMA, Sayaka; TAKAYANAGI, Shuko; WATANABE, Nobuyuki; ONODERA, Masafumi; MATSUNARI, Hitomi; UMEYAMA, Kazuhiro; NAGASHIMA, Hiroshi
Genetically modified pigs that express fluorescent proteins such as green and red fluorescent proteins have become indispensable biomedical research tools in recent years. Cell or tissue transplantation studies using fluorescent markers should be conducted, wherein the xeno-antigenicity of the fluorescent proteins does not affect engraftment or graft survival. Thus, we aimed to create a transgenic (Tg)-cloned pig that was immunologically tolerant to fluorescent protein antigens. In the present study, we generated a Tg-cloned pig harboring a derivative of Plum modified by a single amino acid substitution in the chromophore. The cells and tissues of this Tg-cloned pig expressing the modified Plum (mPlum) did not fluoresce. However, western blot and immunohistochemistry analyses clearly showed that the mPlum had the same antigenicity as Plum. Thus, we have obtained primary proof of principle for creating a cloned pig that is immunologically tolerant to fluorescent protein antigens. PMID:27396383
Swanson-Wagner, Ruth; Briskine, Roman; Schaefer, Robert; Hufford, Matthew B.; Ross-Ibarra, Jeffrey; Myers, Chad L.; Tiffin, Peter; Springer, Nathan M.
Through domestication, humans have substantially altered the morphology of Zea mays ssp. parviglumis (teosinte) into the currently recognizable maize. This system serves as a model for studying adaptation, genome evolution, and the genetics and evolution of complex traits. To examine how domestication has reshaped the transcriptome of maize seedlings, we used expression profiling of 18,242 genes for 38 diverse maize genotypes and 24 teosinte genotypes. We detected evidence for more than 600 genes having significantly different expression levels in maize compared with teosinte. Moreover, more than 1,100 genes showed significantly altered coexpression profiles, reflective of substantial rewiring of the transcriptome since domestication. The genes with altered expression show a significant enrichment for genes previously identified through population genetic analyses as likely targets of selection during maize domestication and improvement; 46 genes previously identified as putative targets of selection also exhibit altered expression levels and coexpression relationships. We also identified 45 genes with altered, primarily higher, expression in inbred relative to outcrossed teosinte. These genes are enriched for functions related to biotic stress and may reflect responses to the effects of inbreeding. This study not only documents alterations in the maize transcriptome following domestication, identifying several genes that may have contributed to the evolution of maize, but highlights the complementary information that can be gained by combining gene expression with population genetic analyses. PMID:22753482
Sun, Tao; Zhang, Lei; Yang, Yanjun; Qi, Jianshuang; Yan, Shufeng; Han, Xiaohua; Wang, Huizhong; Shen, Chenjia
The auxin influx carriers auxin resistant 1/like aux 1 (AUX/LAX), efflux carriers pin-formed (PIN) (together with PIN-like proteins) and efflux/conditional P-glycoprotein (ABCB) are major protein families involved in auxin polar transport. However, how they function in responses to exogenous auxin and abiotic stresses in maize is largely unknown. In this work, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmLAX, ZmPIN, ZmPILS and ZmABCB family genes from maize. The results showed that five ZmLAXs, fifteen ZmPINs, nine ZmPILSs and thirty-five ZmABCBs were mapped on all ten maize chromosomes. Highly diversified gene structures, nonconservative transmembrane helices and tissue-specific expression patterns suggested the possibility of function diversification for these genes. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the expression patterns of ZmLAX, ZmPIN, ZmPILS and ZmABCB genes under exogenous auxin and different environmental stresses. The expression levels of most ZmPIN, ZmPILS, ZmLAX and ZmABCB genes were induced in shoots and were reduced in roots by various abiotic stresses (drought, salt and cold stresses). The opposite expression response patterns indicated the dynamic auxin transport between shoots and roots under abiotic stresses. Analysis of the expression patterns of ZmPIN, ZmPILS, ZmLAX and ZmABCB genes under drought, salt and cold treatment may help us to understand the possible roles of maize auxin transporter genes in responses and tolerance to environmental stresses. PMID:25742625
Xu, Wentao; Yuan, Yanfang; Luo, Yunbo; Bai, Weibin; Zhang, Chunjiao; Huang, Kunlun
More and more stacked GMOs have been developed for more improved functional properties and/or a stronger intended characteristic, such as antipest, improved product efficiency etc. Bt11 x GA21 is a new kind of stacked GM maize developed by Monsanto Company. Since there are no unique flanking sequences in stacked GMOs, up to now, no appropriate method has been reported to accurately detect them. In this passage, a novel universal primer multiplex PCR (UP-M-PCR) was developed and applied as a rapid screening method for the simultaneous detection of five target sequences (NOS, 35S, Bt11 event, GA21 event, and IVR) in maize Bt11 x GA21. This method overcame the disadvantages rooted deeply in conventional multiplex PCR such as complex manipulation, lower sensitivity, self-inhibition and amplification disparity resulting from different primers. What's more, it got a high specificity and had a detection limit of 0.1% (approximates to 38 haploid genome copies). Furthermore, real-time PCR combined with multivariate statistical analysis was used for accurate quantification of stacked GM maize Bt11 x GA21 in 100% GM maize mixture (Bt11 x GA21, Bt11 and GA21). Detection results showed that this method could accurately validate the content of Bt11, GA21 and Bt11 x GA21 in 100% GM mixture with a detection limit of 0.5% (approximates to 200 haploid genome copies) and a low relative standard deviation <5%. All the data proved that this method may be widely applied in event-specific detection of other stacked GMOs in GM-mixture.
Gruber, Helga; Paul, Vijay; Guertler, Patrick; Spiekers, Hubert; Tichopad, Ales; Meyer, Heinrich H D; Muller, Martin
The objective of the study was to track the fate of recombinant Cry1Ab protein in a liquid manure field trial when feeding GM maize MON810 to dairy cows. A validated ELISA was applied for quantification of Cry1Ab in the agricultural chain from GM maize plants, feed, liquid manure and soil to crops grown on manured fields. Starting with 23.7 μg of Cry1Ab g(-1) dry weight GM maize material, a rapid decline of Cry1Ab levels was observed as 2.6% and 0.9% of Cry1Ab from the GM plant were detected in feed and liquid manure, respectively. Half of this residual Cry1Ab persisted during slurry storage for 25 weeks. After application to experimental fields, final degradation of Cry1Ab to below detectable levels in soil was reported. Cry1Ab exhibited a higher rate of degradation compared to total protein in the agricultural processes. Immunoblotting revealed a degradation of the 65 kDa Cry1Ab into immunoreactive fragments of lower size in all analyzed materials.
Swanson-Wagner, Ruth A.; Jia, Yi; DeCook, Rhonda; Borsuk, Lisa A.; Nettleton, Dan; Schnable, Patrick S.
Heterosis is the phenomenon whereby the progeny of particular inbred lines have enhanced agronomic performance relative to both parents. Although several hypotheses have been proposed to explain this fundamental biological phenomenon, the responsible molecular mechanisms have not been determined. The maize inbred lines B73 and Mo17 produce a heterotic F1 hybrid. Global patterns of gene expression were compared in seedlings of these three genotypes by using a microarray that contains 13,999 cDNAs. Using an estimated 15% false discovery rate as a cutoff, 1,367 ESTs (9.8%) were identified as being significantly differentially expressed among genotypes. All possible modes of gene action were observed, including additivity, high- and low-parent dominance, underdominance, and overdominance. The largest proportion of the ESTs (78%; 1,062 of 1,367) exhibited expression patterns that are not statistically distinguishable from additivity. Even so, 22% of the differentially regulated ESTs exhibited nonadditive modes of gene expression. Classified on the basis of significant pairwise comparisons of genotype means, 181 of these 305 nonadditive ESTs exhibited high-parent dominance and 23 exhibited low-parent dominance. In addition, 44 ESTs exhibited underdominance or overdominance. These findings are consistent with the hypothesis that multiple molecular mechanisms, including overdominance, contribute to heterosis. PMID:16641103
Arias-Martín, María; García, Matías; Castañera, Pedro; Ortego, Félix; Farinós, Gema P
The cultivation of Cry1Ab-expressing genetically modified MON810 (Bt maize) has led to public concern in Europe, regarding its impact on nontarget arthropods (NTAs). We have assessed the potential effects of DKC 6451 YG (MON810) maize on canopy NTAs in a farm-scale study performed in Central Spain during 3 years. The study focused on hemipteran herbivores (leafhoppers and planthoppers) and hymenopteran parasitic wasps (mymarids) collected by yellow sticky traps, which accounted for 72% of the total number of insects studied. The dynamics and abundance of these groups varied among years, but no significant differences were found between Bt and non-Bt maize, indicating that Bt maize had no negative effect on these taxa. Nonetheless, the Cry1Ab toxin was detected in 2 different arthropods collected from Bt maize foliage, the cicadellids Zyginidia scutellaris and Empoasca spp. A retrospective power analysis on the arthropod abundance data for our field trials has determined that Z. scutellaris and the family Mymaridae have high capacity to detect differences between the Bt maize and its isogenic counterpart. The use of these canopy NTAs as surrogates for assessing environmental impacts of Bt maize is discussed.
Sahlan, Muhamad; Wiseso, Anggoro; Hermansyah, Heri; Yohda, Masafumi
Cancer is a disease caused by abnormal growth of tissue cells of the body that turn into cancer cells. Apoptin from Chicken Anemia Virus is known to have the ability to trigger apoptosis in cancer cells in vitro and in vivo, but not in normal cells. The production of Apoptin was done on Escherichia coli via plasmid pET9a and modified to improve the efficiency and ease of purification using IMAC nickel, by adding a few tags and cleavage site. The expected result is modified Apoptin and evidence of proteins expressed through SDS-PAGE analysis.
De Souza, Amanda Pereira; Gaspar, Marilia; Da Silva, Emerson Alves; Ulian, Eugênio César; Waclawovsky, Alessandro Jaquiel; Nishiyama, Milton Yutaka; Dos Santos, Renato Vicentini; Teixeira, Marcelo Menossi; Souza, Glaucia Mendes; Buckeridge, Marcos Silveira
Because of the economical relevance of sugarcane and its high potential as a source of biofuel, it is important to understand how this crop will respond to the foreseen increase in atmospheric [CO(2)]. The effects of increased [CO(2)] on photosynthesis, development and carbohydrate metabolism were studied in sugarcane (Saccharum ssp.). Plants were grown at ambient (approximately 370 ppm) and elevated (approximately 720 ppm) [CO(2)] during 50 weeks in open-top chambers. The plants grown under elevated CO(2) showed, at the end of such period, an increase of about 30% in photosynthesis and 17% in height, and accumulated 40% more biomass in comparison with the plants grown at ambient [CO(2)]. These plants also had lower stomatal conductance and transpiration rates (-37 and -32%, respectively), and higher water-use efficiency (c.a. 62%). cDNA microarray analyses revealed a differential expression of 35 genes on the leaves (14 repressed and 22 induced) by elevated CO(2). The latter are mainly related to photosynthesis and development. Industrial productivity analysis showed an increase of about 29% in sucrose content. These data suggest that sugarcane crops increase productivity in higher [CO(2)], and that this might be related, as previously observed for maize and sorghum, to transient drought stress.
Meissle, Michael; Zünd, Jan; Waldburger, Mario; Romeis, Jörg
Maize (Zea mays) pollen is highly nutritious and can be used by predatory arthropods to supplement or replace a carnivorous diet. We demonstrate that maize pollen can be utilized by larvae of the green lacewing, Chrysoperla carnea (Neuroptera: Chrysopidae) under laboratory conditions. Complete development on maize pollen was not possible, but 25% of neonates reached the third instar. When only one instar was fed with pollen and the other two instars with eggs of Ephestia kuehniella (Lepidoptera: Pyralidae), 58–87% of the larvae reached the pupal stage. The experiments included pollen produced by nine cultivars: three genetically modified (GM) cultivars expressing the Bacillus thuringiensis proteins Cry1Ab or Cry3Bb1, their corresponding non-transformed near-isolines, and three conventional cultivars. Maize cultivars were grown in two batches in a glasshouse. Their pollen differed by up to 59% in total protein content, 25% in C:N ratio, and 14% in grain diameter, but the differences were inconsistent and depended on the batch. Lacewing performance was not affected by maize cultivar. For environmental risk assessment of GM plants, in planta studies must consider the variability among conventional cultivars, individual plants, batches, and environmental conditions when evaluating the ecological significance of differences observed between GM and near-isolines. PMID:25082074
Aspergillus flavus is a pathogenic fungus producing alfatoxins that cause significant economic losses in maize production. This study analyzes the differences in expression levels of maize genes in response to A. flavus infection and aflatoxin accumulation. Identification of defense related genes an...
Zhao, Xiongwei; Nie, Shujun; Li, Yuhua; Zhang, Zhiming; Shen, Yaou; Chen, Qi; Lu, Yanli; Lan, Hai; Zhou, Shufeng; Gao, Shibin; Pan, Guangtang; Lin, Haijian
Nitrogen (N) is an essential nutrient for plants, and it directly affects grain yield and protein content in cereal crops. Plant root systems are not only critical for anchorage in the soil, but also for N acquisition. Therefore, genes controlling root development might also affect N uptake by plants. In this study, the responses of nitrogen on root architecture of mutant rtcs and wild-type of maize were investigated by morphological and physiological analysis. Subsequently, we performed a comparative RNA-Seq analysis to compare gene expression profiles between mutant rtcs roots and wild-type roots under different N conditions. We identified 786 co-modulated differentially expressed genes (DEGs) related to root development. These genes participated in various metabolic processes. A co-expression cluster analysis and a cis-regulatory motifs analysis revealed the importance of the AP2-EREBP transcription factor family in the rtcs-dependent regulatory network. Some genotype-specific DEGs contained at least one LBD motif in their promoter region. Further analyses of the differences in gene transcript levels between rtcs and wild-type under different N conditions revealed 403 co-modulated DEGs with distinct functions. A comparative analysis revealed that the regulatory network controlling root development also controlled gene expression in response to N-deficiency. Several AP2-EREBP family members involved in multiple hormone signaling pathways were among the DEGs. These transcription factors might play important roles in the rtcs-dependent regulatory network related to root development and the N-deficiency response. Genes encoding the nitrate transporters NRT2-1, NAR2.1, NAR2.2, and NAR2.3 showed much higher transcript levels in rtcs than in wild-type under normal-N conditions. This result indicated that the LBD gene family mainly functions as transcriptional repressors, as noted in other studies. In summary, using a comparative RNA-Seq-based approach, we identified
McGovern, Vicki L; Massoni-Laporte, Aurélie; Wang, Xueyong; Le, Thanh T; Le, Hao T; Beattie, Christine E; Rich, Mark M; Burghes, Arthur H M
Spinal muscular atrophy is caused by loss of the SMN1 gene and retention of SMN2. The SMN2 copy number inversely correlates with phenotypic severity and is a modifier of disease outcome. The SMN2 gene essentially differs from SMN1 by a single nucleotide in exon 7 that modulates the incorporation of exon 7 into the final SMN transcript. The majority of the SMN2 transcripts lack exon 7 and this leads to a SMN protein that does not effectively oligomerize and is rapidly degraded. However the SMN2 gene does produce some full-length SMN and the SMN2 copy number along with how much full-length SMN the SMN2 gene makes correlates with severity of the SMA phenotype. However there are a number of discordant SMA siblings that have identical haplotypes and SMN2 copy number yet one has a milder form of SMA. It has been suggested that Plastin3 (PLS3) acts as a sex specific phenotypic modifier where increased expression of PLS3 modifies the SMA phenotype in females. To test the effect of PLS3 overexpression we have over expressed full-length PLS3 in SMA mice. To ensure no disruption of functionality or post-translational processing of PLS3 we did not place a tag on the protein. PLS3 protein was expressed under the Prion promoter as we have shown previously that SMN expression under this promoter can rescue SMA mice. High levels of PLS3 mRNA were expressed in motor neurons along with an increased level of PLS3 protein in total spinal cord, yet there was no significant beneficial effect on the phenotype of SMA mice. Specifically, neither survival nor the fundamental electrophysiological aspects of the neuromuscular junction were improved upon overexpression of PLS3 in neurons.
Wang, Xueyong; Le, Thanh T.; Le, Hao T.; Beattie, Christine E.; Rich, Mark M.; Burghes, Arthur H. M.
Spinal muscular atrophy is caused by loss of the SMN1 gene and retention of SMN2. The SMN2 copy number inversely correlates with phenotypic severity and is a modifier of disease outcome. The SMN2 gene essentially differs from SMN1 by a single nucleotide in exon 7 that modulates the incorporation of exon 7 into the final SMN transcript. The majority of the SMN2 transcripts lack exon 7 and this leads to a SMN protein that does not effectively oligomerize and is rapidly degraded. However the SMN2 gene does produce some full-length SMN and the SMN2 copy number along with how much full-length SMN the SMN2 gene makes correlates with severity of the SMA phenotype. However there are a number of discordant SMA siblings that have identical haplotypes and SMN2 copy number yet one has a milder form of SMA. It has been suggested that Plastin3 (PLS3) acts as a sex specific phenotypic modifier where increased expression of PLS3 modifies the SMA phenotype in females. To test the effect of PLS3 overexpression we have over expressed full-length PLS3 in SMA mice. To ensure no disruption of functionality or post-translational processing of PLS3 we did not place a tag on the protein. PLS3 protein was expressed under the Prion promoter as we have shown previously that SMN expression under this promoter can rescue SMA mice. High levels of PLS3 mRNA were expressed in motor neurons along with an increased level of PLS3 protein in total spinal cord, yet there was no significant beneficial effect on the phenotype of SMA mice. Specifically, neither survival nor the fundamental electrophysiological aspects of the neuromuscular junction were improved upon overexpression of PLS3 in neurons. PMID:26134627
Tollot, Marie; Assmann, Daniela; Becker, Christian; Altmüller, Janine; Dutheil, Julien Y; Wegner, Carl-Eric; Kahmann, Regine
The biotrophic basidiomycete fungus Ustilago maydis causes smut disease in maize. Hallmarks of the disease are large tumors that develop on all aerial parts of the host in which dark pigmented teliospores are formed. We have identified a member of the WOPR family of transcription factors, Ros1, as major regulator of spore formation in U. maydis. ros1 expression is induced only late during infection and hence Ros1 is neither involved in plant colonization of dikaryotic fungal hyphae nor in plant tumor formation. However, during late stages of infection Ros1 is essential for fungal karyogamy, massive proliferation of diploid fungal cells and spore formation. Premature expression of ros1 revealed that Ros1 counteracts the b-dependent filamentation program and induces morphological alterations resembling the early steps of sporogenesis. Transcriptional profiling and ChIP-seq analyses uncovered that Ros1 remodels expression of about 30% of all U. maydis genes with 40% of these being direct targets. In total the expression of 80 transcription factor genes is controlled by Ros1. Four of the upregulated transcription factor genes were deleted and two of the mutants were affected in spore development. A large number of b-dependent genes were differentially regulated by Ros1, suggesting substantial changes in this regulatory cascade that controls filamentation and pathogenic development. Interestingly, 128 genes encoding secreted effectors involved in the establishment of biotrophic development were downregulated by Ros1 while a set of 70 "late effectors" was upregulated. These results indicate that Ros1 is a master regulator of late development in U. maydis and show that the biotrophic interaction during sporogenesis involves a drastic shift in expression of the fungal effectome including the downregulation of effectors that are essential during early stages of infection.
Qiu, Fang; Guo, Ling; Wen, Tsui-Jung; Liu, Feng; Ashlock, Daniel A; Schnable, Patrick S
To enhance gene discovery, expressed sequence tag (EST) projects often make use of cDNA libraries produced using diverse mixtures of mRNAs. As such, expression data are lost because the origins of the resulting ESTs cannot be determined. Alternatively, multiple libraries can be prepared, each from a more restricted source of mRNAs. Although this approach allows the origins of ESTs to be determined, it requires the production of multiple libraries. A hybrid approach is reported here. A cDNA library was prepared using 21 different pools of maize (Zea mays) mRNAs. DNA sequence "bar codes" were added during first-strand cDNA synthesis to uniquely identify the mRNA source pool from which individual cDNAs were derived. Using a decoding algorithm that included error correction, it was possible to identify the source mRNA pool of more than 97% of the ESTs. The frequency at which a bar code is represented in an EST contig should be proportional to the abundance of the corresponding mRNA in the source pool. Consistent with this, all ESTs derived from several genes (zein and adh1) that are known to be exclusively expressed in kernels or preferentially expressed under anaerobic conditions, respectively, were exclusively tagged with bar codes associated with mRNA pools prepared from kernel and anaerobically treated seedlings, respectively. Hence, by allowing for the retention of expression data, the bar coding of cDNA libraries can enhance the value of EST projects.
Tollot, Marie; Assmann, Daniela; Becker, Christian; Altmüller, Janine; Dutheil, Julien Y.; Wegner, Carl-Eric; Kahmann, Regine
The biotrophic basidiomycete fungus Ustilago maydis causes smut disease in maize. Hallmarks of the disease are large tumors that develop on all aerial parts of the host in which dark pigmented teliospores are formed. We have identified a member of the WOPR family of transcription factors, Ros1, as major regulator of spore formation in U. maydis. ros1 expression is induced only late during infection and hence Ros1 is neither involved in plant colonization of dikaryotic fungal hyphae nor in plant tumor formation. However, during late stages of infection Ros1 is essential for fungal karyogamy, massive proliferation of diploid fungal cells and spore formation. Premature expression of ros1 revealed that Ros1 counteracts the b-dependent filamentation program and induces morphological alterations resembling the early steps of sporogenesis. Transcriptional profiling and ChIP-seq analyses uncovered that Ros1 remodels expression of about 30% of all U. maydis genes with 40% of these being direct targets. In total the expression of 80 transcription factor genes is controlled by Ros1. Four of the upregulated transcription factor genes were deleted and two of the mutants were affected in spore development. A large number of b-dependent genes were differentially regulated by Ros1, suggesting substantial changes in this regulatory cascade that controls filamentation and pathogenic development. Interestingly, 128 genes encoding secreted effectors involved in the establishment of biotrophic development were downregulated by Ros1 while a set of 70 “late effectors” was upregulated. These results indicate that Ros1 is a master regulator of late development in U. maydis and show that the biotrophic interaction during sporogenesis involves a drastic shift in expression of the fungal effectome including the downregulation of effectors that are essential during early stages of infection. PMID:27332891
The dek18 mutant of maize has decreased auxin content in kernels. Molecular and functional characterization of this mutant line offers the possibility to better understand auxin biology in maize seed development. Seeds of the dek18 mutants are smaller compared to wild type seeds and the vegetative d...
Maize fine streak virus (MFSV) is an emerging virus of maize that is transmitted by an insect vector, the leafhopper called Graminella nigrifrons. Virus transmission by the leafhopper requires that the virus enter into and multiply in insect cells, tissues and organs before being transmitted to a ne...
Córdoba-Rodríguez, Guadalupe; Vargas, Mario H; Ruiz, Víctor; Carbajal, Verónica; Campos-Bedolla, Patricia; Mercadillo-Herrera, Paulina; Arreola-Ramírez, José Luis; Segura-Medina, Patricia
There is mounting evidence that 5-hydroxytryptamine (5-HT) plays a role in asthma. However, scarce information exists about the pulmonary expression of 5-HT receptors and its modification after allergic sensitization. In the present work, we explored the expression of 5-HT1A, 5-HT2A, 5-HT3, 5-HT4, 5-ht5a, 5-HT6, and 5-HT7 receptors in lungs from control and sensitized guinea pigs through qPCR and Western blot. In control animals, mRNA from all receptors was detectable in lung homogenates, especially from 5-HT2A and 5-HT4 receptors. Sensitized animals had decreased mRNA expression of 5-HT2A and 5-HT4 receptors and increased that of 5-HT7 receptor. In contrast, they had increased protein expression of 5-HT2A receptor in bronchial epithelium and of 5-HT4 receptor in lung parenchyma. The degree of airway response to the allergic challenge was inversely correlated with mRNA expression of the 5-HT1A receptor. In summary, our results showed that major 5-HT receptor subtypes are constitutively expressed in the guinea pig lung, and that allergic sensitization modifies the expression of 5-HT2A, 5-HT4, and 5-HT7 receptors.
Malmanche, Nicolas; Clark, Denise V
The first committed step in the purine de novo synthesis pathway is performed by amidophosphoribosyltransferase (EC 184.108.40.206) or Prat. Drosophila melanogaster Prat is an essential gene with a promoter that lacks a TATA-box and initiator element and has multiple transcription start sites with a predominant start site. To study the regulation of Prat expression in the adult eye, we used the Prat:bw reporter gene, in which the Prat coding region was replaced with the brown (bw) coding region. The pale-orange eye color of a single copy of Prat:bw prompted us to use a multicopy array of Prat:bw that was derived using P transposase mutagenesis and produces a darker-orange eye color in a bw(D); st genetic background. We used a 13-copy array of Prat:bw as a tool to recover dominant EMS-induced mutations that affect the expression of the transgene. After screening 21,000 F(1)s for deviation from the orange eye color, we isolated 23 dominant modifiers: 21 suppressors (1 Y-linked, 5 X-linked, 4 2-linked, and 11 3-linked) and 2 enhancers (1 2-linked and 1 3-linked). Quantification of their effect on endogenous Prat gene expression, using RT-PCR in young adult fly heads, identifies a subset of modifiers that are candidates for genes involved in regulating Prat expression. PMID:12930749
Bosch, Maurice; Mayer, Claus-Dieter; Cookson, Alan; Donnison, Iain S.
Despite the economic importance of grasses as food, feed, and energy crops, little is known about the genes that control their cell wall synthesis, assembly, and remodelling. Here a detailed transcriptome analysis that allowed the identification of genes involved in grass cell wall biogenesis is provided. Differential gene expression profiling, using maize oligonucleotide arrays, was used to identify genes differentially expressed between an elongating internode, containing cells exhibiting primary cell wall synthesis, and an internode that had just ceased elongation and in which many cells were depositing secondary cell wall material. This is one of only a few studies specifically aimed at the identification of cell wall-related genes in grasses. Analysis identified new candidate genes for a role in primary and secondary cell wall biogenesis in grasses. The results suggest that many proteins involved in cell wall processes during normal development are also recruited during defence-related cell wall remodelling events. This work provides a platform for studies in which candidate genes will be functionally tested for involvement in cell wall-related processes, increasing our knowledge of cell wall biogenesis and its regulation in grasses. Since several grasses are currently being developed as lignocellulosic feedstocks for biofuel production, this improved understanding of grass cell wall biogenesis is timely, as it will facilitate the manipulation of traits favourable for sustainable food and biofuel production. PMID:21402660
Loza-Rubio, Elizabeth; Rojas-Anaya, Edith; López, Juan; Olivera-Flores, María Teresa; Gómez-Lim, Miguel; Tapia-Pérez, Graciela
The introduction of exogenous genes into plants permits the development of a new generation of biological products, i.e., edible vaccines. Cereals, especially maize, have been the systems of choice for the expression of antigenic proteins because the proteins can be expressed at high levels in the kernel and stored for prolonged periods without excessive deterioration. The utilization of plant-derived antigens for oral delivery provides an alternative strategy for the control of pathogens in animals compared to the current vaccine administration methods, such as injection. However, there is some doubt about the efficacy of these types of vaccines in polygastric animals due to the features of their digestive system. Here, we report the efficacy of an edible vaccine against rabies evaluated in sheep. Kernels containing different doses of G protein (0.5, 1, 1.5 and 2mg) were given in a single dose by the oral route. Cumulative survival was better in groups that received 2mg of G protein and for the positive control (inactivated rabies vaccine); this observation was supported by the presence of neutralizing antibodies. Animals in the control group died after challenge. The degree of protection achieved for 2mg of G protein was comparable to that conferred by a commercial vaccine. In conclusion, this is the first study in which an orally administered edible vaccine showed efficacy in a polygastric model.
Huo, Yongjin; Wang, Meiping; Wei, Yangyang; Xia, Zongliang
The psbA (encoding D1 protein) plays an important role in protecting photosystem II (PSII) from oxidative damage in higher plants. In our previous study, the role of the psbA from maize (Zea mays. L) in response to SO2 stress was characterized. To date, information about the involvement of the psbA gene in drought response is scarce. Here we found that overexpression (OE) of ZmpsbA showed increased D1 protein abundance and enhanced drought stress tolerance in tobacco. The drought-tolerant phenotypes of the OE lines were accompanied by increases of key antioxidant enzymes SOD, CAT, and POD activities, but decreases of hydrogen peroxide, malondialdehyde, and ion leakage. Further investigation showed that the OE plants had much less reductions than the wild-type in the net photosynthesis rate (Pn), stomatal conductance (Gs), and the maximal photochemical efficiency of PSII (Fv/Fm) during drought stress; indicating that OE of ZmpsbA may alleviate photosynthesis inhibition during drought. qRT-PCR analysis revealed that there was significantly increased expression of NtLEA5, NtERD10C, NtAREB, and NtCDPK2 in ZmpsbA-OE lines. Together, our results indicate that ZmpsbA improves drought tolerance in tobacco possibly by alleviating photosynthesis reduction, reducing reactive oxygen species accumulation and membrane damage, and modulating stress defense gene expression. ZmpsbA could be exploited for engineering drought-tolerant plants in molecular breeding of crops.
Brouquisse, Renaud; Evrard, Adeline; Rolin, Dominique; Raymond, Philippe; Roby, Claude
The effects of mannose (Man) and glucose (Glc) on central metabolism, proteolysis, and expression of the root starvation-induced protease (RSIP; F. James, R. Brouquisse, C. Suire, A. Pradet, P. Raymond  Biochem J 320: 283–292) were investigated in maize (Zea mays L. cv DEA) root tips. Changes in metabolite concentrations (sugars, ester-phosphates, adenine nucleotides, and amino acids) were monitored using in vivo and in vitro 13C- and 31P-NMR spectroscopy, in parallel with the changes in respiration rates, protein contents, proteolytic activities, and RSIP amounts. The inhibition of proteolysis, the decrease in proteolytic activities, and the repression of RSIP expression triggered by Man, at concentrations usually used to study sugar signaling (2 and 10 mm), were found to be related to a drop of energy metabolism, primarily due to a Man-induced Pi sequestration. However, when supplied at low concentration (2 mm) and with the adequate phosphate concentration (30 mm), energy metabolism was restored and Man repressed proteolysis similarly to Glc, when provided at the same concentration. These results indicate that Man should be used with caution as a Glc analog to study signalization by sugars in plants because possible signaling effects may be hindered by Pi sequestration. PMID:11244127
Singh, Kirmender; Bhattacharyya, A. B.
Gummel Symmetry Test (GST) has been a benchmark industry standard for MOSFET models and is considered as one of important tests by the modeling community. BSIM4 MOSFET model fails to pass GST as the drain current equation is not symmetrical because drain and source potentials are not referenced to bulk. BSIM6 MOSFET model overcomes this limitation by taking all terminal biases with reference to bulk and using proper velocity saturation (v -E) model. The drain current equation in BSIM6 is charge based and continuous in all regions of operation. It, however, adopts a complicated method to compute source and drain charges. In this work we propose to use conventional charge based method formulated by Enz for obtaining simpler analytical drain current expression that passes GST. For this purpose we adopt two steps: (i) In the first step we use a modified first-order hyperbolic v -E model with adjustable coefficients which is integrable, simple and accurate, and (ii) In the second we use a multiplying factor in the modified first-order hyperbolic v -E expression to obtain correct monotonic asymptotic behavior around the origin of lateral electric field. This factor is of empirical form, which is a function of drain voltage (vd) and source voltage (vs) . After considering both the above steps we obtain drain current expression whose accuracy is similar to that obtained from second-order hyperbolic v -E model. In modified first-order hyperbolic v -E expression if vd and vs is replaced by smoothing functions for the effective drain voltage (vdeff) and effective source voltage (vseff), it will as well take care of discontinuity between linear to saturation regions of operation. The condition of symmetry is shown to be satisfied by drain current and its higher order derivatives, as both of them are odd functions and their even order derivatives smoothly pass through the origin. In strong inversion region and technology node of 22 nm the GST is shown to pass till sixth
Lülf, Anna-Theresa; Freudenstein, Astrid; Marr, Lisa; Sutter, Gerd; Volz, Asisa
In cell culture infections with vaccinia virus the number of counted virus particles is substantially higher than the number of plaques obtained by titration. We found that standard vaccine preparations of recombinant Modified Vaccinia virus Ankara produce only about 20-30% plaque-forming virions in fully permissive cell cultures. To evaluate the biological activity of the non-plaque-forming particles, we generated recombinant viruses expressing fluorescent reporter proteins under transcriptional control of specific viral early and late promoters. Live cell imaging and automated counting by fluorescent microscopy indicated that virtually all virus particles can enter cells and switch on viral gene expression. Although most of the non-plaque-forming infections are arrested at the level of viral early gene expression, we detected activation of late viral transcription in 10-20% of single infected cells. Thus, non-plaque-forming particles are biologically active, and likely contribute to the immunogenicity of vaccinia virus vaccines.
García-Cañas, Virginia; González, Ramón; Cifuentes, Alejandro
In this work, four different fluorescent intercalating dyes are compared for the ultrasensitive CGE-LIF detection of DNA from transgenic maize in flours. The fluorescent intercalating dyes compared are YOPRO-1, SYBR-Green-I, Ethidium bromide (EthBr), and EnhanCE. For all the four dyes optimum concentrations are established, and efficient separations of DNA fragments ranging in size from 80 to 1000 bp are obtained. The comparative study demonstrates that SYBR-Green-I and YOPRO-1 provide better limits of detection (LODs) than EnhanCE or EthBr (i.e., LODs are, respectively, 700, 1000, 11300, and 97400 zmol, calculated for a 200-bp DNA fragment). Separations using YOPRO-1 are faster than those using SYBR-Green-I (30 min vs 47 min for the analysis of the 80-1000 bp DNA fragments). Also, separations using YOPRO-1 are more efficient than those using SYBR-Green-I (e.g., 2.4 x 10(6) plates/m vs 1.6 x 10(6) plates/m, respectively, calculated for the 200-bp fragment). Also, buffer depletion and cost per analysis are worse with SYBR-Green-I than with YOPRO-1. Therefore, YOPRO-1 was selected as the preferred intercalating dye. Using this fluorescent compound, analysis time reproducibility for the CGE-LIF separation of the DNA fragments is determined to be better than 1.7% (% RSD, n = 10) within the same day, and better than 1.9% (% RSD, n = 30) for three different days. Moreover, the fluorescence signal obtained using this dye is shown to vary linearly with the DNA concentration in the range studied, i.e., 1-500 ng/microL. It is demonstrated that by using this method 0.01% of transgenic maize can be detected in flour by direct injection of the PCR-amplified sample.
Glant, Tibor T.; Besenyei, Timea; Kádár, András; Kurkó, Júlia; Tryniszewska, Beata; Gál, János; Soós, Györgyi; Szekanecz, Zoltán; Hoffmann, Gyula; Block, Joel A.; Katz, Robert S.; Mikecz, Katalin; Rauch, Tibor A.
Objective The aim of this study was to identify epigenetic factors that are implicated in the pathogenesis of rheumatoid arthritis (RA) and to explore the therapeutic potential of the targeted inhibition of these factors. Methods PCR arrays were utilized to investigate the expression profile of genes that encod key epigenetic regulator enzymes. Mononuclear cells from RA patients and mice were monitored for gene expression changes, in association with arthritis development in murine models of RA. Selected genes were further characterized by quantitative real-time PCR, Western blot and flow cytometry methods. The targeted inhibition of the upregulated enzymes was studied in arthritic mice. Results A set of genes with arthritis-specific expression was identified by the PCR arrays. Aurora kinase A and B, both of which were highly expressed in arthritic mice and treatment naïve RA patients, were selected for detailed analysis. Elevated Aurora kinase expression was accompanied with an increased phosphorylation of histone H3, which promotes proliferation of T lymphocytes. Treatment with VX-680, a pan-Aurora kinase inhibitor, promoted B cell apoptosis, provided significant protection against the onset, and attenuated the inflammatory reactions in arthritic mice. Conclusions Arthritis development is accompanied the changes in the expression of a number of epigenome-modifying enzymes. Drug-induced downregulation of the Aurora kinases, among other targets, seems to be sufficient to treat experimental arthritis. Development of new therapeutics that target the Aurora kinases can potentially improve RA management. PMID:23653330
Falaleeva, Marina; Surface, Justin; Shen, Manli; de la Grange, Pierre; Stamm, Stefan
The loss of two gene clusters encoding small nucleolar RNAs, SNORD115 and SNORD116 contribute to Prader-Willi syndrome (PWS), the most common syndromic form of obesity in humans. SNORD115 and SNORD116 are considered to be orphan C/D box snoRNAs (SNORDs) as they do not target rRNAs or snRNAs. SNORD115 exhibits sequence complementarity towards the serotonin receptor 2C, but SNORD116 shows no extended complementarities to known RNAs. To identify molecular targets, we performed genome-wide array analysis after overexpressing SNORD115 and SNORD116 in HEK 293T cells, either alone or together. We found that SNORD116 changes the expression of over 200 genes. SNORD116 mainly changed mRNA expression levels. Surprisingly, we found that SNORD115 changes SNORD116's influence on gene expression. In similar experiments, we compared gene expression in post-mortem hypothalamus between individuals with PWS and aged-matched controls. The synopsis of these experiments resulted in 23 genes whose expression levels were influenced by SNORD116. Together our results indicate that SNORD115 and SNORD116 influence expression levels of multiple genes and modify each other activity.
Easton, D.F.; Ponder, B.A.J. ); Huson, S.M. ); Ponder, M.A. )
Neurofibromatosis (NF) type 1 (NF1) is notable for its variable expression. To determine whether variation in expression has an inherited component, the authors examined 175 individuals in 48 NF families, including six MZ twin pairs. Three quantitative traits were scored - number of cafe-au-lait patches, number of cutaneous neurofibromas, and head circumference; and five binary traits were scored - the presence or absence of plexiform neurofibromas, optic gliomas, scoliosis, epilepsy, and referral for remedial education. For cafe-au-lait patches and neurofibromas, correlation was highest between MZ twins, less high between first-degree relatives, and lower still between more distant relatives. The high correlation between distant relatives suggests that the type of mutation at the NF1 locus itself plays only a minor role. All of the five binary traits, with the exception of plexiformneurofibromas, also showed significant familial clustering. The familial effects for these traits were consistent with polygenic effects, but there were insufficient data to rule out other models, including a significant effect of different NF1 mutations. There was no evidence of any association between the different traits in affected individuals. The authors conclude that the phenotypic expression of NF1 is to a large extent determined by the genotype at other [open quotes]modifying[close quotes] loci and that these modifying genes are trait specific. 22 refs., 8 tabs.
Qian, Baoyun; Li, Xia; Liu, Xiaolong; Chen, Pingbo; Ren, Chengang; Dai, Chuanchao
We determined the effects of endogenous nitric oxide and Ca(2+) on photosynthesis and gene expression in transgenic rice plants (PC) over-expressing the maize C4pepc gene, which encodes phosphoenolpyruvate carboxylase (PEPC) under drought. In this study, seedlings were subjected to PEG 6000 treatments using PC and wild type (WT; Kitaake). The results showed that, compared with WT, PC had higher relative water content (RWC) and net photosynthetic rate (Pn) under drought. During a 2-day re-watering treatment, Pn recovered faster in PC than in WT. Further analyses showed that, under the drought treatment, the amount of endogenous hydrogen peroxide (H2O2) increased in WT mainly via NADPH oxidase. While in PC, the endogenous nitric oxide (NO) content increased via nitrate reductase and nitric oxide synthase on day 2 of the drought treatment and day 1 of the re-watering treatment. After 2 days of drought treatment, PC also showed higher PEPC activity, calcium content, phospholipase D (PLD) activity, C4-pepc and NAC6 transcript levels, and protein kinase activity as compared with PC without treatment. These changes did not occur in WT. Correlation analysis also proved NO associated with these indicators in PC. Based on these results, there was a particular molecular mechanism of drought tolerance in PC. The mechanism is related to the signaling processes via NO and Ca(2+) involving the protein kinase and the transcription factor, resulted in up-regulation of PEPC activity and its gene expression, such as C4pepc. Some genes encode antioxidant system, cu/zn-sod as well, which promote antioxidant system to clear MDA and superoxide anion radical, thereby conferring drought tolerance.
Tremblay, Jacques P
A new technology, called CRISPR, derived from the immune system of bacteria, uses a Cas9 nuclease and a guided RNA complementary to a 20 nucleotides sequence of a gene to induce double strand DNA breaks. This permits to modify specifically the targeted gene in plant, animal and human cells. Variants of the technique also permit to reduce or increase the expression of a selected gene. This technology may thus be used not only to understand the role of a gene but also to develop therapies for hereditary and acquired diseases.
Tamasloukht, Barek; Wong Quai Lam, Mary Sarah-Jane; Martinez, Yves; Tozo, Koffi; Barbier, Odile; Jourda, Cyril; Jauneau, Alain; Borderies, Gisèle; Balzergue, Sandrine; Renou, Jean-Pierre; Huguet, Stéphanie; Martinant, Jean Pierre; Tatout, Christophe; Lapierre, Catherine; Barrière, Yves; Goffner, Deborah; Pichon, Magalie
Cinnamoyl-CoA reductase (CCR), which catalyses the first committed step of the lignin-specific branch of monolignol biosynthesis, has been extensively characterized in dicot species, but few data are available in monocots. By screening a Mu insertional mutant collection in maize, a mutant in the CCR1 gene was isolated named Zmccr1–. In this mutant, CCR1 gene expression is reduced to 31% of the residual wild-type level. Zmccr1– exhibited enhanced digestibility without compromising plant growth and development. Lignin analysis revealed a slight decrease in lignin content and significant changes in lignin structure. p-Hydroxyphenyl units were strongly decreased and the syringyl/guaiacyl ratio was slightly increased. At the cellular level, alterations in lignin deposition were mainly observed in the walls of the sclerenchymatic fibre cells surrounding the vascular bundles. These cell walls showed little to no staining with phloroglucinol. These histochemical changes were accompanied by an increase in sclerenchyma surface area and an alteration in cell shape. In keeping with this cell type-specific phenotype, transcriptomics performed at an early stage of plant development revealed the down-regulation of genes specifically associated with fibre wall formation. To the present authors’ knowledge, this is the first functional characterization of CCR1 in a grass species. PMID:21493812
High expression levels of a transgene can be very useful, making a transgene easier to evaluate for safety and efficacy. High expression levels can also increase the economic benefit of the production of high value proteins in transgenic plants. The goal of this research is to determine if recurre...
Introduction Regulated neurotransmitter actions in the mammalian central nervous system determine brain function and control peripheral organs and behavior. Although drug-seeking behaviors, including alcohol consumption, depend on central neurotransmission, modification of neurotransmitter actions in specific brain nuclei remains challenging. Herein, we report a novel approach for neurotransmission modification in vivo by transplantation of stem cells engineered to take up the neurotransmitter dopamine (DA) efficiently through the action of the human dopamine transporter (hDAT). As a functional test in mice, we used voluntary alcohol consumption, which is known to release DA in nucleus accumbens (NAC), an event hypothesized to help maintain drug-seeking behavior. We reasoned that reducing extracellular DA levels, by engrafting into NAC DA-sequestering stem cells expressing hDAT, would alter alcohol intake. Methods We have generated a neural stem cell line stably expressing the hDAT. Uptake kinetics of DA were determined to select a clone for transplantation. These genetically modified stem cells (or cells transfected with a construct lacking the hDAT sequence) were transplanted bilaterally into the NAC of wild-type mice trained to consume 10% alcohol in a two-bottle free-choice test for alcohol consumption. Alcohol intake was then ascertained for 1 week after transplantation, and brain sections through the NAC were examined for surviving grafted cells. Results Modified stem cells expressed hDAT and uptaken DA selectively via hDAT. Mice accustomed to drinking 10% ethanol by free choice reduced their alcohol consumption after being transplanted with hDAT-expressing stem cells. By contrast, control stem cells lacked that effect. Histologic examination revealed surviving stem cells in the NAC of all engrafted brains. Conclusions Our findings represent proof of principle suggesting that genetically engineered stem cells can be useful for exploring the role of
Wilton, Steve D; Fletcher, Susan
Antisense oligomers initially showed promise as compounds to modify gene expression, primarily through RNaseH induced degradation of the target transcript. Expansion of the field has led to new chemistries capable of invoking different mechanisms, including suppression of protein synthesis by translational blockade and gene silencing using short interfering RNAs. It is now apparent that the majority of the eukaryotic genome is transcribed and non-protein coding RNAs have been implicated in the regulation of gene expression at many levels. This review considers potential therapeutic applications of antisense oligomers to modify gene expression, primarily by interfering with the process of exon recognition and intron removal during gene transcript splicing. While suppression of gene expression will be necessary to address some conditions, it is likely that antisense oligomer splice modification will have extensive clinical application. Pre-mRNA splicing is a tightly co-ordinated, multifactorial process that can be disrupted by antisense oligomers in a highly specific manner to suppress aberrant splicing, remove exons to by-pass nonsense or frame-shifting mutations or influence exon selection to alter spliceoform ratios. Manipulation of splicing patterns has been applied to a diverse range of conditions, including b-thalassemia, Duchenne muscular dystrophy, spinal muscular atrophy and certain cancers. Alternative exon usage has been identified as a major mechanism for generating diversity from a limited repertoire of genes in higher eukaryotes. Considering that the majority of all human primary gene transcripts are reportedly alternatively spliced, intervention at the level of pre-mRNA processing is likely to become increasingly significant in the fight against genetic and acquired disorders.
Shu, Yinghua; Zhang, Yanyan; Feng, Yuanjiao; Wang, Jianwu
The cultivation of genetically modified plants (GMP) has raised concerns regarding the plants’ ecological safety. A greenhouse experiment was conducted to assess the impact of five seasons of continuous Bt (Bacillus thuringiensis) maize cultivation on the colonisation and community structure of the non-target organisms arbuscular mycorrhizal fungi (AMF) in the maize roots, bulk soils and rhizospheric soils using the terminal restriction fragment length polymorphism (T-RFLP) analysis of the 28S ribosomal DNA and sequencing methods. AMF colonisation was significantly higher in the two Bt maize lines that express Cry1Ab, 5422Bt1 (event Bt11) and 5422CBCL (MON810) than in the non-Bt isoline 5422. No significant differences were observed in the diversity of the AMF community between the roots, bulk soils and rhizospheric soils of the Bt and non-Bt maize cultivars. The AMF genus Glomus was dominant in most of the samples, as detected by DNA sequencing. A clustering analysis based on the DNA sequence data suggested that the sample types (i.e., the samples from the roots, bulk soils or rhizospheric soils) might have greater influence on the AMF community phylotypes than the maize cultivars. This study indicated that the Cry1Ab protein has minor effects on the AMF communities after five seasons of continuous Bt maize cultivation. PMID:26717324
Li, Zhili; Wang, Jigui; Yuan, Daoli; Wang, Shuang; Sun, Jiazeng; Yi, Bao; Hou, Qiang; Mao, Yaping; Liu, Weiquan
Canine distemper virus (CDV) and rabies virus (RV) are two important pathogens of the dog. CDV, a member of the morbillivirus genus, has shown promise as an expression vector. The glycoprotein from RV is a main contributor to protective immunity and capable of eliciting the production of virus-neutralizing antibodies. In this study, we recovered an attenuated strain of canine distemper virus and constructed a recombinant virus, rCDV-RV-G, expressing a modified (R333Q) rabies virus glycoprotein (RV-G) of RV Flury strain LEP. RV-G expression by the recombinant viruses was confirmed. Furthermore, G was proved to be incorporated into the surface of CDV particles. While replication of the recombinant virus was slightly reduced compared with the parental CDV, it stably expressed the RV-G over ten serial passages. Inoculation of mice induced specific neutralizing antibodies against both RV-G and CDV. Therefore, the rCDV-RV-G has the potential as a vaccine that may be used to control rabies virus infection in dogs and other animals.
Xu, Wang-Jie; Wang, Zhao-Xia; Qiao, Zhong-Dong
Serial analysis of gene expression (SAGE) is a powerful technique to study gene expression at the genome level. However, a disadvantage of the shortness of SAGE tags is that it prevents further study of SAGE library data, thus limiting extensive application of the SAGE method in gene expression studies. However, this problem can be solved by extension of the SAGE tags to 3' cDNAs. Therefore, several methods based on PCR have been developed to generate a 3' longer fragment cDNA corresponding to a SAGE tag. The list of modified methods is extensive, and includes rapid RT-PCR analysis of unknown SAGE tags (RAST-PCR), generation of longer cDNA fragments from SAGE tags for gene identification (GLGI), a high-throughput GLGI procedure, reverse SAGE (rSAGE), two-step analysis of unknown SAGE tags (TSAT-PCR), etc. These procedures are constantly being updated because they have characteristics and advantages that can be shared. Development of these methods has promoted the widespread use of the SAGE technique, and has accelerated the speed of studies of large-scale gene expression.
Cloning and expression analyses of sucrose non-fermenting-1-related kinase 1 (SnRK1b) gene during development of sorghum and maize endosperm and its implicated role in sugar-to-starch metabolic transition.
Jain, Mukesh; Li, Qin-Bao; Chourey, Prem S
A full-length cDNA clone, SbSnRK1b (1530 bp, GenBank accession no. EF544393), encoding a putative serine/threonine protein kinase homologue of yeast (Saccharomyces cerevisiae) SNF1, was isolated from developing endosperm of sorghum [Sorghum bicolor (L.) Moench]. Multiple sequence alignment data showed a phylogenetic affiliation of the sorghum clone with the SnRK1b group of protein kinases that are highly expressed in cereal seed endosperm. The DNA gel blot analyses indicated that SbSnRK1b gene is present as a single- or low copy number gene in sorghum. The RNA and protein gel blot analyses confirmed the expression of SbSnRK1b in developing sorghum caryopses, overlapping with the starch biosynthesis phase, 12-24 days after fertilization. In situ hybridization and immunolocalization data resolved the spatial specificity of SbSnRK1b expression in the basal endosperm transfer cell layer, the unique port of assimilate unloading in the growing sorghum seed. Expression of SbSnRK1b was also evident in the developing sorghum microspores, coincident with the onset of starch deposition phase. As in sorghum, similar spatiotemporal specificity of SnRK1b expression was observed during maize (Zea mays L.) seed development. However, discordant in situ hybridization and immunolocalization data indicated that the expression of SbSnRK1b homologue in maize is under posttranscriptional control during endosperm development.
Yue, Jing; Li, Cong; Zhao, Qian; Zhu, Dengyun; Yu, Jingjuan
Maize seed storage proteins are a major source of human and livestock consumption. However, these proteins have poor nutritional value, because they are deficient in lysine and tryptophan. Much research has been done to elevate the lysine content by reducing zein content or regulating the activities of key enzymes in lysine metabolism. Using the naturally lysine-rich protein genes, sb401 and SBgLR, from potato, we previously increased the lysine and protein contents of maize seeds. Here, we examined another natural lysine-rich protein gene, GhLRP, from cotton, which increased the lysine content of transgenic maize seeds at levels varying from 16.2% to 65.0% relative to the wild-type. The total protein content was not distinctly different, except in the six transgenic lines. The lipid and starch levels did not differ substantially in Gossypium hirsutum L. lysine-rich protein (GhLRP) transgenic kernels when compared to wild-type. The agronomic characteristics of all the transgenic maize were also normal. GhLRP is a high-lysine protein candidate gene for increasing the lysine content of maize. This study provided a valuable model system for improving maize lysine content.
Fu, Jianming; Ristic, Zoran
We previously reported that transgenic wheat (Triticum aestivum L.) carrying a maize (Zea mays L.) gene (Zmeftu1) for chloroplast protein synthesis elongation factor, EF-Tu, displays reduced thermal aggregation of leaf proteins, reduced injury to photosynthetic membranes (thylakoids), and enhanced rate of CO(2) fixation following exposure to heat stress (18 h at 45 degrees C) [Fu et al. in Plant Mol Biol 68:277-288, 2008]. In the current study, we investigated the segregation pattern and expression of the transgene Zmeftu1 and determined the grain yield of transgenic plants after exposure to a brief heat stress (18 h at 45 degrees C). We also assessed thermal aggregation of soluble leaf proteins in transgenic plants, testing the hypothesis that increased levels of EF-Tu will lead to a non-specific protection of leaf proteins against thermal aggregation. The transgenic wheat displayed a single-gene pattern of segregation of Zmeftu1. Zmeftu1 was expressed, and the transgenic plants synthesized and accumulated three anti-EF-Tu cross-reacting polypeptides of similar molecular mass but different pI, suggesting the possibility of posttranslational modification of this protein. The transgenic plants also showed better grain yield after exposure to heat stress compared with their non-transgenic counterparts. Soluble leaf proteins of various molecular masses displayed lower thermal aggregation in transgenic than in non-transgenic wheat. The results suggest that overexpression of chloroplast EF-Tu can be beneficial to wheat tolerance to heat stress. Moreover, the results also support the hypothesis that EF-Tu contributes to heat tolerance by acting as a molecular chaperone and protecting heat-labile proteins from thermal aggregation in a non-specific manner.
Fu, Junjie; Falke, K Christin; Thiemann, Alexander; Schrag, Tobias A; Melchinger, Albrecht E; Scholten, Stefan; Frisch, Matthias
The performance of hybrids can be predicted with gene expression data from their parental inbred lines. Implementing such prediction approaches in breeding programs promises to increase the efficiency of hybrid breeding. The objectives of our study were to compare the accuracy of prediction models employing multiple linear regression (MLR), partial least squares regression (PLS), support vector machine regression (SVM), and transcriptome-based distances (D(B)). For a factorial of 7 flint and 14 dent maize lines, the grain yield of the hybrids was assessed and the gene expression of the parental lines was profiled with a 56k microarray. The accuracy of the prediction models was measured by the correlation between predicted and observed yield employing two cross-validation schemes. The first modeled the prediction of hybrids when testcross data are available for both parental lines (type 2 hybrids), and the second modeled the prediction of hybrids when no testcross data for the parental lines were available (type 0 hybrids). MLR, SVM, and PLS resulted in a high correlation between predicted and observed yield for type 2 hybrids, whereas for type 0 hybrids D(B) had greater prediction accuracy. The regression methods were robust to the choice of the set of profiled genes and required only a few hundred genes. In contrast, for an accurate hybrid prediction with D(B), 1,000-1,500 genes were required, and the prediction accuracy depended strongly on the set of profiled genes. We conclude that for prediction within one set of genetic material MLR is a promising approach, and for transferring prediction models from one set of genetic material to a related one, the transcriptome-based distance D(B) is most promising.
Wacher-Rodarte, Maria Del Carmen; Trejo-Muñúzuri, Tanya Paulina; Montiel-Aguirre, Jesús Fernando; Drago-Serrano, Maria Elisa; Gutiérrez-Lucas, Raúl L; Castañeda-Sánchez, Jorge Ismael; Sainz-Espuñes, Teresita
Pozol is a handcrafted nonalcoholic Mayan beverage produced by the spontaneous fermentation of maize dough by lactic acid bacteria. Lactic acid bacteria (LAB) are carriers of chromosomal encoded multidrug-resistant efflux pumps genes that can be transferred to pathogens and/or confer resistance to compounds released during the fermentation process causing food spoiling. The aim of this study was to evaluate the antibiotic sensibility and the transcriptional expression of ABC-type efflux pumps in LAB isolated from pozol that contributes to multidrug resistance. Analysis of LAB and Staphylococcus (S.) aureus ATCC 29213 and ATCC 6538 control strains to antibiotic susceptibility, minimal inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) to ethidium bromide were based in "standard methods" whereas the ethidium bromide efflux assay was done by fluorometric assay. Transcriptional expression of efflux pumps was analyzed by RT-PCR. LAB showed antibiotic multiresistance profiles, moreover, Lactococcus (L.) lactis and Lactobacillus (L.) plantarum displayed higher ethidium bromide efflux phenotype than S. aureus control strains. Ethidium bromide resistance and ethidium bromide efflux phenotypes were unrelated with the overexpression of lmrD in L. lactics, or the underexpression of lmrA in L. plantarum and norA in S. aureus. These findings suggest that, moreover, the analyzed efflux pumps genes, other unknown redundant mechanisms may underlie the antibiotic resistance and the ethidium bromide efflux phenotype in L. lactis and L. plantarum. Phenotypic and molecular drug multiresistance assessment in LAB may improve a better selection of the fermentation starter cultures used in pozol, and to control the antibiotic resistance widespread and food spoiling for health safety.
Pedrón, Valeria T; Taravini, Irene R E; Induni, Andrea S; Balerio, Graciela N
In previous studies, we have reported sex-related differences during morphine withdrawal. We have also shown that the GABA(B) agonist baclofen (BAC) was able to prevent the morphine withdrawal syndrome in male as well as in female mice. Considering that early gene expression is induced by drugs of abuse, we evaluated the expression of c-Fos in several brain areas, in mice of either sex during naloxone (NAL)-precipitated withdrawal, and after pretreatment with BAC. Swiss-Webster prepubertal mice were rendered dependent by i.p. injection of morphine (2 mg/kg), twice daily for 9 days. On the 10th day, dependent mice were divided into two groups: the withdrawal group received NAL (6 mg/kg, i.p.) after the last dose of morphine, while the prevention group received BAC (2 mg/kg, i.p.) before NAL. Thirty minutes after NAL, animals were sacrificed by transcardial perfusion. Brains were removed and slices were obtained to perform immunohistochemical studies. Our results show a significant decrease in c-Fos expression in hippocampal dentate gyrus, CA3, and CA1 areas of morphine withdrawn males, vs. their control group. Conversely, in females, the number of c-Fos positive nuclei was not modified in any of the areas studied. BAC pretreatment had no effect on the decreased c-Fos expression in morphine withdrawn males. The sexual dimorphism observed here confirms the greater sensitivity of males over females in their response to morphine. The preventive action of BAC on the expression of morphine withdrawal would not be related to an effect on c-Fos expression.
Heterosis has been widely used in agriculture, but the molecular mechanism for this remains largely elusive. In Arabidopsis hybrids and allopolyploids, increased photosynthetic and metabolic activities are linked to altered expression of circadian clock regulators, including CIRCADIAN CLOCK ASSOCIAT...
MaizeCyc is a catalog of known and predicted metabolic and transport pathways that enables plant researchers to graphically represent the metabolome of maize (Zea mays), thereby supporting integrated systems-biology analysis. Supported analyses include molecular and genetic/phenotypic profiling (e.g...
Cázares-Domínguez, Vicenta; Ochoa, Sara A.; Cruz-Córdova, Ariadnna; Rodea, Gerardo E.; Escalona, Gerardo; Olivares, Alma L.; Olivares-Trejo, José de Jesús; Velázquez-Guadarrama, Norma; Xicohtencatl-Cortes, Juan
Staphylococcus aureus is an opportunistic pathogen that colonizes human hosts and causes a wide variety of diseases. Two interacting regulatory systems called agr (accessory gene regulator) and sar (staphylococcal accessory regulator) are involved in the regulation of virulence factors. The aim of this study was to evaluate the effect of vancomycin on hld and spa gene expression during the exponential and post-exponential growth phases in multidrug-resistant (MDR) S. aureus. Methods: Antibiotic susceptibility was evaluated by the standard microdilution method. The phylogenetic profile was obtained by pulsed-field gel electrophoresis (PFGE). Polymorphisms of agr and SCCmec (staphylococcal cassette chromosome mec) were analyzed by multiplex polymerase chain reaction (PCR). The expression levels of hld and spa were analyzed by reverse transcription-PCR. An enzyme-linked immunosorbent assay (ELISA) was performed to detect protein A, and biofilm formation was analyzed via crystal violet staining. Results: In total, 60.60% (20/33) of S. aureus clinical isolates were MDR. Half (10/20) of the MDR S. aureus isolates were distributed in subcluster 10, with >90% similarity among them. In the isolates of this subcluster, a high prevalence (100%) for the agrII and the cassette SCCmec II polymorphisms was found. Our data showed significant increases in hld expression during the post-exponential phase in the presence and absence of vancomycin. Significant increases in spa expression, protein A production and biofilm formation were observed during the post-exponential phase when the MDR S. aureus isolates were challenged with vancomycin. Conclusion: The polymorphism agrII, which is associated with nosocomial isolates, was the most prevalent polymorphism in MDR S. aureus. Additionally, under our study conditions, vancomycin modified hld and spa expression in these clinical isolates. Therefore, vancomycin may regulate alternative systems that jointly participate in the regulation of
infectious diseases as a modifying factor for HAE severity, large-scale studies would be needed to statistically associate such expression pattern to the development of this rare disease. PMID:23688356
Breeding of maize, Zea mays, has improved insect resistance, but the genetic and biochemical basis of many of these improvements is unknown. Maize oligonucleotide microarrays were utilized to identify differentially expressed genes in leaves of three maize inbreds, parents Oh40B and W8 and progeny O...
Mortality of western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae due to feeding on MON863 transgenic maize (Zea mays L.) expressing the Cry3Bb1 protein relative to survivorship on maize with the same genetic background without the gene (isoline maize) was evaluated at three Missour...
Hoben, Gwendolyn M; Athanasiou, Kyriacos A
Modulation of the actin cytoskeleton in chondrocytes has been used to prevent or reverse dedifferentiation and to enhance protein synthesis. We have hypothesized that an actin-modifying agent, staurosporine, could be used with fibrochondrocytes to increase the gene expression and synthesis of critical fibrocartilage proteins. A range of concentrations (0.1-100 nM) was applied to fibrochondrocytes in monolayer and evaluated after 24 h and after 4 days. High-dose staurosporine treatment (10-100 nM) increased cartilage oligomeric matrix protein 60- to 500-fold and aggrecan gene expression two-fold. This effective range of staurosporine was then applied to scaffoldless tissue-engineered fibrochondrocyte constructs for 4 weeks. Whereas glycosaminoglycan synthesis was not affected, collagen content doubled, from 27.6 +/- 8.8 microg in the untreated constructs to 55.2 +/- 12.2 microg per construct with 100 nM treatment. When analyzed for specific collagens, the 10-nM group showed a significant increase in collagen type I content, whereas collagen type II was unaffected. A concomitant dose-dependent reduction was noted in construct contraction, reflecting the actin-disrupting action of staurosporine. Thus, staurosporine increases the gene expression for important matrix proteins and can be used to enhance matrix production and reduce contraction in tissue-engineered fibrocartilage constructs.
Copy-number alterations are widespread in animal and plant genomes, but their immediate impact on gene expression is still unclear. In animals, copy-number alterations usually exhibit dosage effects, except for sex chromosomes that tend to be dosage compensated. In plants, genes within small duplica...
Evaluation of resistance or susceptibility of corn inbreds to infection by Aspergillus flavus was evaluated by a kernel screening assay. A GFP-expressing strain of A. flavus was used to accomplish this study to measure fungal spread and aflatoxin levels in real time. Among the four inbreds tested, ...
Zhang, Xiaolan; Douglas, Ryan N.; Strable, Josh; Lee, Michelle; Buckner, Brent; Janick-Buckner, Diane; Schnable, Patrick S.; Timmermans, Marja C.P.; Scanlon, Michael J.
The maize (Zea mays) gene RAGGED SEEDLING2-R (RGD2-R) encodes an ARGONAUTE7-like protein required for the biogenesis of trans-acting small interfering RNA, which regulates the accumulation of AUXIN RESPONSE FACTOR3A transcripts in shoots. Although dorsiventral polarity is established in the narrow and cylindrical leaves of rgd2-R mutant plants, swapping of adaxial/abaxial epidermal identity occurs and suggests a model wherein RGD2 is required to coordinate dorsiventral and mediolateral patterning in maize leaves. Laser microdissection-microarray analyses of the rgd2-R mutant shoot apical meristem identified a novel gene, PUNCTATE VASCULAR EXPRESSION1 (PVE1), that is down-regulated in rgd2-R mutant apices. Transcripts of PVE1 provide an early molecular marker for vascular morphogenesis. Reverse genetic analyses suggest that PVE1 functions during vascular development and in mediolateral and dorsiventral patterning of maize leaves. Molecular genetic analyses of PVE1 and of rgd2-R;pve1-M2 double mutants suggest a model wherein PVE1 functions downstream of RGD2 in a pathway that intersects and interacts with the trans-acting small interfering RNA pathway. PMID:22669891
Piquemal, Joel; Chamayou, Simon; Nadaud, Isabelle; Beckert, Michel; Barrière, Yves; Mila, Isabelle; Lapierre, Catherine; Rigau, Joan; Puigdomenech, Pere; Jauneau, Alain; Digonnet, Catherine; Boudet, Alain-Michel; Goffner, Deborah; Pichon, Magalie
Transgenic maize (Zea mays) plants were generated with a construct harboring a maize caffeic acid O-methyltransferase (COMT) cDNA in the antisense (AS) orientation under the control of the maize Adh1 (alcohol dehydrogenase) promoter. Adh1-driven β-glucuronidase expression was localized in vascular tissues and lignifying sclerenchyma, indicating its suitability in transgenic experiments aimed at modifying lignin content and composition. One line of AS plants, COMT-AS, displayed a significant reduction in COMT activity (15%–30% residual activity) and barely detectable amounts of COMT protein as determined by western-blot analysis. In this line, transgenes were shown to be stably integrated in the genome and transmitted to the progeny. Biochemical analysis of COMT-AS showed: (a) a strong decrease in Klason lignin content at the flowering stage, (b) a decrease in syringyl units, (c) a lower p-coumaric acid content, and (d) the occurrence of unusual 5-OH guaiacyl units. These results are reminiscent of some characteristics already observed for the maize bm3 (brown-midrib3) mutant, as well as for COMT down-regulated dicots. However, as compared with bm3, COMT down-regulation in the COMT-AS line is less severe in that it is restricted to sclerenchyma cells. To our knowledge, this is the first time that an AS strategy has been applied to modify lignin biosynthesis in a grass species. PMID:12481050
Toyokawa, Chihana; Shobu, Misaki; Tsukamoto, Rie; Okamura, Saki; Honda, Yoichi; Kamitsuji, Hisatoshi; Izumitsu, Kousuke; Suzuki, Kazumi; Irie, Toshikazu
We studied the role of genes encoding the cAMP-dependent protein kinase A catalytic subunit (PKAc) in the ligninolytic system in Pleurotus ostreatus. The wild-type P. ostreatus strain PC9 has two PKAc-encoding genes: PKAc1 and PKAc2 (protein ID 114122 and 85056). In the current study, PKAc1 and PKAc2 were fused with a β-tubulin promoter and introduced into strain PC9 to produce the overexpression strains PKAc1-97 and PKAc2-69. These strains showed significantly higher transcription levels of isozyme genes encoding lignin-modifying enzymes than strain PC9, but the specific gene expression patterns differed between the two recombinant strains. Both recombinants showed 2.05-2.10-fold faster degradation of beechwood lignin than strain PC9. These results indicate that PKAc plays an important role in inducing the wood degradation system in P. ostreatus.
Martin, Judith A; Murphy, Richard A; Power, Ronan F G
Two heterologous phytases from Aspergillus awamori and Aspergillus fumigatus obtained from submerged cultures of genetically modified fungal strains in addition to two commercially available phytase preparations (Allzyme and Natuphos phytases) were purified to homogeneity using a combination of ultrafiltration, gel filtration and ion exchange. The purified preparations were used in subsequent characterisation studies, in which Western Immunoblot analysis, pH and temperature optima, thermal stability and substrate specificity were assessed. A. fumigatus phyA phytase expressed in A. awamori exhibited activity over a broad pH range together with an increased temperature optimum, and slightly enhanced thermal stability compared to the other phytases tested, and is thus a promising candidate for animal feed applications. This particular phytase retains activity over a wide range of pH values characteristic of the digestive tract and could conceivably be more suited to the increasingly higher feed processing temperatures being utilised today, than the corresponding phytases from Aspergillus niger.
Kiran, Nagavalli S; Polanská, Lenka; Fohlerová, Radka; Mazura, Pavel; Válková, Martina; Smeral, Miloslav; Zouhar, Jan; Malbeck, Jirí; Dobrev, Petre I; Machácková, Ivana; Brzobohaty, Bretislav
The activity of the phytohormone cytokinin depends on a complex interplay of factors such as its metabolism, transport, stability, and cellular/tissue localization. O-glucosides of zeatin-type cytokinins are postulated to be storage and/or transport forms, and are readily deglucosylated. Transgenic tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) plants were constructed over-expressing Zm-p60.1, a maize beta-glucosidase capable of releasing active cytokinins from O- and N3-glucosides, to analyse its potential to perturb zeatin metabolism in planta. Zm-p60.1 in chloroplasts isolated from transgenic leaves has an apparent K(m) more than 10-fold lower than the purified enzyme in vitro. Adult transgenic plants grown in the absence of exogenous zeatin were morphologically indistinguishable from the wild type although differences in phytohormone levels were observed. When grown on medium containing zeatin, inhibition of root elongation was apparent in all seedlings 14 d after sowing (DAS). Between 14 and 21 DAS, the transgenic seedlings accumulated fresh weight leading later (28-32 DAS) to ectopic growths at the base of the hypocotyl. The development of ectopic structures correlated with the presence of the enzyme as demonstrated by histochemical staining. Cytokinin quantification showed that transgenic seedlings grown on medium containing zeatin accumulate active metabolites like zeatin riboside and zeatin riboside phosphate and this might lead to the observed changes. The presence of the enzyme around the base of the hypocotyl and later, in the ectopic structures themselves, suggests that the development of these structures is due to the perturbance in zeatin metabolism caused by the ectopic presence of Zm-p60.1.
Background Alfalfa (Medicago sativa) is an important forage crop in North America owing to its high biomass production, perennial nature and ability to fix nitrogen. Feruloyl esterase (EC 220.127.116.11) hydrolyzes ester linkages in plant cell walls and has the potential to further improve alfalfa as biomass for biofuel production. Results In this study, faeB [GenBank:AJ309807] was synthesized at GenScript and sub-cloned into a novel pEACH vector containing different signaling peptides to target type B ferulic acid esterase (FAEB) proteins to the apoplast, chloroplast, endoplasmic reticulum and vacuole. Four constructs harboring faeB were transiently expressed in Nicotiana leaves, with FAEB accumulating at high levels in all target sites, except chloroplast. Stable transformed lines of alfalfa were subsequently obtained using Agrobacterium tumefaciens (LBA4404). Out of 136 transgenic plants regenerated, 18 independent lines exhibited FAEB activity. Subsequent in vitro digestibility and Fourier transformed infrared spectroscopy (FTIR) analysis of FAEB-expressing lines showed that they possessed modified cell wall morphology and composition with a reduction in ester linkages and elevated lignin content. Consequently, they were more recalcitrant to digestion by mixed ruminal microorganisms. Interestingly, delignification by alkaline peroxide treatment followed by exposure to a commercial cellulase mixture resulted in higher glucose release from transgenic lines as compared to the control line. Conclusion Modifying cell wall crosslinking has the potential to lower recalcitrance of holocellulose, but also exhibited unintended consequences on alfalfa cell wall digestibility due to elevated lignin content. The combination of efficient delignification treatment (alkaline peroxide) and transgenic esterase activity complement each other towards efficient and effective digestion of transgenic lines. PMID:24650274
Cheeke, Tanya E; Pace, Brian A; Rosenstiel, Todd N; Cruzan, Mitchell B
Crop plants genetically modified for the expression of Bacillus thuringiensis (Bt) insecticidal toxins have broad appeal for reducing insect damage in agricultural systems, yet questions remain about the impact of Bt plants on symbiotic soil organisms. Here, arbuscular mycorrhizal fungal (AMF) colonization of transgenic maize isoline Bt 11 (expressing Cry1Ab) and its non-Bt parental line (Providence) was evaluated under different fertilizer level and spore density scenarios. In a three-way factorial design, Bt 11 and non-Bt maize were inoculated with 0, 40, or 80 spores of Glomus mosseae and treated weekly with 'No' (0 g L(-1) ), 'Low' (0.23 g L(-1) ), or 'High' (1.87 g L(-1) ) levels of a complete fertilizer and grown for 60 days in a greenhouse. While no difference in AMF colonization was detected between the Bt 11 and Providence maize cultivars in the lower spore/higher fertilizer treatments, microcosm experiments demonstrated a significant reduction in AMF colonization in Bt 11 maize roots in the 80 spore treatments when fertilizer was limited. These results confirm previous work indicating an altered relationship between this Bt 11 maize isoline and AMF and demonstrate that the magnitude of this response is strongly dependent on both nutrient supply and AMF spore inoculation level.
Augustine, Robert C.; Rytz, Thérèse C.
In response to abiotic and biotic challenges, plants rapidly attach small ubiquitin-related modifier (SUMO) to a large collection of nuclear proteins, with studies in Arabidopsis (Arabidopsis thaliana) linking SUMOylation to stress tolerance via its modification of factors involved in chromatin and RNA dynamics. Despite this importance, little is known about SUMOylation in crop species. Here, we describe the plant SUMO system at the phylogenetic, biochemical, and transcriptional levels with a focus on maize (Zea mays). In addition to canonical SUMOs, land plants encode a loosely constrained noncanonical isoform and a variant containing a long extension upstream of the signature β-grasp fold, with cereals also expressing a novel diSUMO polypeptide bearing two SUMO β-grasp domains in tandem. Maize and other cereals also synthesize a unique SUMO-conjugating enzyme variant with more restricted expression patterns that is enzymatically active despite a distinct electrostatic surface. Maize SUMOylation primarily impacts nuclear substrates, is strongly induced by high temperatures, and displays a memory that suppresses subsequent conjugation. Both in-depth transcript and conjugate profiles in various maize organs point to tissue/cell-specific functions for SUMOylation, with potentially significant roles during embryo and endosperm maturation. Collectively, these studies define the organization of the maize SUMO system and imply important functions during seed development and stress defense. PMID:27208252
Truter, J; Van Hamburg, H; Van Den Berg, J
The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.
Kaliberov, Sergey A.; Kaliberova, Lyudmila N.; Lu, Zhi Hong; Preuss, Meredith A.; Barnes, Justin A.; Stockard, Cecil R.; Grizzle, William E.; Arbeit, Jeffrey M.; Curiel, David T.
Adenovirus serotype 5 (Ad5) vectors are well suited for gene therapy. However, tissue-selective transduction by systemically administered Ad5-based vectors is confounded by viral particle sequestration in the liver. Hexon-modified Ad5 expressing reporter gene under transcriptional control by the immediate/early cytomegalovirus (CMV) or the Roundabout 4 receptor (Robo4) enhancer/promoter were characterized by growth in cell culture, stability in vitro, gene transfer in the presence of human coagulation factor X, and biodistribution in mice. The obtained data demonstrate the utility of the Robo4 promoter in an Ad5 vector context. Substitution of the hypervariable region 7 (HVR7) of the Ad5 hexon with HVR7 from Ad serotype 3 resulted in decreased liver tropism and dramatically altered biodistribution of gene expression. The results of these studies suggest that the combination of liver detargeting using a genetic modification of hexon with an endothelium-specific transcriptional control element produces an additive effect in the improvement of Ad5 biodistribution. PMID:24210128
Kaliberov, Sergey A; Kaliberova, Lyudmila N; Hong Lu, Zhi; Preuss, Meredith A; Barnes, Justin A; Stockard, Cecil R; Grizzle, William E; Arbeit, Jeffrey M; Curiel, David T
Adenovirus serotype 5 (Ad5) vectors are well suited for gene therapy. However, tissue-selective transduction by systemically administered Ad5-based vectors is confounded by viral particle sequestration in the liver. Hexon-modified Ad5 expressing reporter gene under transcriptional control by the immediate/early cytomegalovirus (CMV) or the Roundabout 4 receptor (Robo4) enhancer/promoter was characterized by growth in cell culture, stability in vitro, gene transfer in the presence of human coagulation factor X, and biodistribution in mice. The obtained data demonstrate the utility of the Robo4 promoter in an Ad5 vector context. Substitution of the hypervariable region 7 (HVR7) of the Ad5 hexon with HVR7 from Ad serotype 3 resulted in decreased liver tropism and dramatically altered biodistribution of gene expression. The results of these studies suggest that the combination of liver detargeting using a genetic modification of hexon with an endothelium-specific transcriptional control element produces an additive effect in the improvement of Ad5 biodistribution.
Zolochevska, Olga; Diaz-Quiñones, Adriana O; Ellis, Jayne; Figueiredo, Marxa L
Prostate cancer is frequently associated with bone metastases, where the crosstalk between tumor cells and key cells of the bone microenvironment (osteoblasts, osteoclasts, immune cells) amplifies tumor growth. We have explored the potential of a novel cytokine, interleukin-27 (IL-27), for inhibiting this malignant crosstalk, and have examined the effect of autocrine IL-27 on prostate cancer cell gene expression, as well as the effect of paracrine IL-27 on gene expression in bone and T cells. In prostate tumor cells, IL-27 upregulated genes related to its signaling pathway while downregulating malignancy-related receptors and cytokine genes involved in gp130 signaling, as well as several protease genes. In both undifferentiated and differentiated osteoblasts, IL-27 modulated upregulation of genes related to its own signaling pathway as well as pro-osteogenic genes. In osteoclasts, IL-27 downregulated several genes typically involved in malignancy and also downregulated osteoclastogenesis-related genes. Furthermore, an osteogenesis-focused real-time PCR array revealed a more extensive profile of pro-osteogenic gene changes in both osteoblasts and osteoclasts. In T-lymphocyte cells, IL-27 upregulated several activation-related genes and also genes related to the IL-27 signaling pathway and downregulated several genes that could modulate osteoclastogenesis. Overall, our results suggest that IL-27 may be able to modify interactions between prostate tumor and bone microenvironment cells and thus could be used as a multifunctional therapeutic for restoring bone homeostasis while treating metastatic prostate tumors.
Steudle, E.; Murrmann, M.; Peterson, C. A.
The effects of puncturing the endodermis of young maize roots (Zea mays L.) on their transport properties were measured using the root pressure probe. Small holes with a diameter of 18 to 60 [mu]m were created 70 to 90 mm from the tips of the roots by pushing fine glass tubes radially into them. Such wounds injured about 10-2 to 10-3% of the total surface area of the endodermis, which, in these hydroponically grown roots, had developed a Casparian band but no suberin lamellae. The small injury to the endodermis caused the original root pressure, which varied from 0.08 to 0.19 MPa, to decrease rapidly (half-time = 10-100 s) and substantially to a new steady-state value between 0.02 and 0.07 MPa. The radial hydraulic conductivity (Lpr) of control (uninjured) roots determined using hydrostatic pressure gradients as driving forces was larger by a factor of 10 than that determined using osmotic gradients (averages: Lpr [hydrostatic] = 2.7 x 10-7 m s-1 MPa-1; Lpr [osmotic] = 2.2 x 10-8 m s-1 MPa-1; osmotic solute: NaCl). Puncturing the endodermis did not result in measurable increases in hydraulic conductivities measured by either method. Thus, the endodermis was not rate-limiting root Lpr: apparently the hydraulic resistance of roots was more evenly distributed over the entire root tissue. However, puncturing the endodermis did substantially change the reflection ([sigma]sr) and permeability (Psr) coefficients of roots for NaCl, indicating that the endodermis represented a considerable barrier to the flow of nutrient ions. Values of [sigma]sr decreased from 0.64 to 0.41 (average) and Psr increased by a factor of 2.6, i.e. from 3.8 x 10-9 to 10.1 x 10.-9 m s-1(average). The roots recovered from puncturing after a time and regained root pressure. Measurable increases in root pressure became apparent as soon as 0.5 to 1 h after puncturing, and original or higher root pressures were attained 1.5 to 20 h after injury. However, after recovery roots often did not maintain a
Arvanitoyannis, Ioannis S; Vlachos, Antonios
Maize is one of the most important cereals because of its numerous applications in processed foods where it is the major or minor component. Apart from maize authenticity issues related to cultivar and geographical origin (national and/or international level), there is another important issue related to genetically modified maize. Various objective parameters such as fatty acids, phenolic compounds, pigments, heavy metals were determined in conjunction with subjective (sensory analysis) in order to identify the maize authenticity. However, the implementation of multivariate analysis (principal component analysis, cluster analysis, discriminant analysis, canonical analysis) is of great importance toward reaching valid conclusions on authenticity issues. This review summarized the most important finding of both objective and subjective evaluations of maize in five comprehensive tables in conjunction with the discussion.
Schaeffer, Mary L; Harper, Lisa C; Gardiner, Jack M; Andorf, Carson M; Campbell, Darwin A; Cannon, Ethalinda K S; Sen, Taner Z; Lawrence, Carolyn J
First released in 1991 with the name MaizeDB, the Maize Genetics and Genomics Database, now MaizeGDB, celebrates its 20th anniversary this year. MaizeGDB has transitioned from a focus on comprehensive curation of the literature, genetic maps and stocks to a paradigm that accommodates the recent release of a reference maize genome sequence, multiple diverse maize genomes and sequence-based gene expression data sets. The MaizeGDB Team is relatively small, and relies heavily on the research community to provide data, nomenclature standards and most importantly, to recommend future directions, priorities and strategies. Key aspects of MaizeGDB's intimate interaction with the community are the co-location of curators with maize research groups in multiple locations across the USA as well as coordination with MaizeGDB's close partner, the Maize Genetics Cooperation--Stock Center. In this report, we describe how the MaizeGDB Team currently interacts with the maize research community and our plan for future interactions that will support updates to the functional and structural annotation of the B73 reference genome.
Mwita, Liberata; Chan, Wai Yin; Pretorius, Theresa; Lyantagaye, Sylvester L; Lapa, Svitlana V; Avdeeva, Lilia V; Reva, Oleg N
Despite successful use of Plant Growth Promoting Rhizobacteria (PGPR) in agriculture, little is known about specific mechanisms of gene regulation facilitating the effective communication between bacteria and plants during plant colonization. Active PGPR strain Bacillus atrophaeus UCMB-5137 was studied in this research. RNA sequencing profiles were generated in experiments where root exudate stimulations were used to mimic interactions between bacteria and plants. It was found that the gene regulation in B. atrophaeus UCMB-5137 in response to the root exudate stimuli differed from the reported gene regulation at similar conditions in B. amyloliquefaciens FZB42, which was considered as a paradigm PGPR. This difference was explained by hypersensitivity of UCMB-5137 to the root exudate stimuli impelling it to a sessile root colonization behavior through the CcpA-CodY-AbrB regulation. It was found that the transcriptional factor DegU also could play an important role in gene regulations during plant colonization. A significant stress caused by the root exudates on in vitro cultivated B. atrophaeus UCMB-5137 was noticed and discussed. Multiple cases of conflicted gene regulations showed scantiness of our knowledge on the regulatory network in Bacillus. Some of these conflicted regulations could be explained by interference of non-coding RNA (ncRNA). Search through differential expressed intergenic regions revealed 49 putative loci of ncRNA regulated by the root exudate stimuli. Possible target mRNA were predicted and a general regulatory network of B. atrophaeus UCMB-5137 genome was designed.
Meissle, Michael; Romeis, Jörg; Bigler, Franz
The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests.
Davis, G L; McMullen, M D; Baysdorfer, C; Musket, T; Grant, D; Staebell, M; Xu, G; Polacco, M; Koster, L; Melia-Hancock, S; Houchins, K; Chao, S; Coe, E H
We have constructed a 1736-locus maize genome map containing1156 loci probed by cDNAs, 545 probed by random genomic clones, 16 by simple sequence repeats (SSRs), 14 by isozymes, and 5 by anonymous clones. Sequence information is available for 56% of the loci with 66% of the sequenced loci assigned functions. A total of 596 new ESTs were mapped from a B73 library of 5-wk-old shoots. The map contains 237 loci probed by barley, oat, wheat, rice, or tripsacum clones, which serve as grass genome reference points in comparisons between maize and other grass maps. Ninety core markers selected for low copy number, high polymorphism, and even spacing along the chromosome delineate the 100 bins on the map. The average bin size is 17 cM. Use of bin assignments enables comparison among different maize mapping populations and experiments including those involving cytogenetic stocks, mutants, or quantitative trait loci. Integration of nonmaize markers in the map extends the resources available for gene discovery beyond the boundaries of maize mapping information into the expanse of map, sequence, and phenotype information from other grass species. This map provides a foundation for numerous basic and applied investigations including studies of gene organization, gene and genome evolution, targeted cloning, and dissection of complex traits. PMID:10388831
Williamson, J D; Scandalios, J G
In this paper we describe the distinctive responses of the maize catalases to the plant growth regulator abscisic acid (ABA). We analyzed RNA and enzyme accumulation in excised maize embryos and found that each catalase responded differently to exogenously applied ABA. Levels of Cat1 transcript and enzyme activity rapidly increased. In contrast, levels of Cat2 transcript and protein decreased, while Cat3 transcript levels were not affected. In developing kernels of the ABA-deficient/biosynthetic viviparous mutant vp5, lower levels of Cat1 RNA correlated with lower endogenous ABA levels when compared to measured levels in comparably aged wild-type siblings from the same ear. The maize vp1 mutant line is morphologically insensitive to normal endogenous levels of ABA. Analysis of the response of Cat1 to exogenously applied ABA in mutant and wild-type vp1 sibling embryos suggests that, unlike other ABA-responsive genes analyzed to date, the Vp1 gene product is not essential for the ABA-mediated regulation of Cat1. The significance of these responses to ABA in defining the roles of the various CATs in maize is discussed. Images PMID:1388272
Maize VP1 enhancement of ABA sensitivity in roots is B3 independent. ABA and VP1 mediated suppression of auxin induced lateral root development is B3 independent. Arabidopsis transgenic system to delineate B3 dependent and COAR domain dependent regulatory functions of VP1. Analyses of ectopic ABA re...
Davis, G L; McMullen, M D; Baysdorfer, C; Musket, T; Grant, D; Staebell, M; Xu, G; Polacco, M; Koster, L; Melia-Hancock, S; Houchins, K; Chao, S; Coe, E H
We have constructed a 1736-locus maize genome map containing1156 loci probed by cDNAs, 545 probed by random genomic clones, 16 by simple sequence repeats (SSRs), 14 by isozymes, and 5 by anonymous clones. Sequence information is available for 56% of the loci with 66% of the sequenced loci assigned functions. A total of 596 new ESTs were mapped from a B73 library of 5-wk-old shoots. The map contains 237 loci probed by barley, oat, wheat, rice, or tripsacum clones, which serve as grass genome reference points in comparisons between maize and other grass maps. Ninety core markers selected for low copy number, high polymorphism, and even spacing along the chromosome delineate the 100 bins on the map. The average bin size is 17 cM. Use of bin assignments enables comparison among different maize mapping populations and experiments including those involving cytogenetic stocks, mutants, or quantitative trait loci. Integration of nonmaize markers in the map extends the resources available for gene discovery beyond the boundaries of maize mapping information into the expanse of map, sequence, and phenotype information from other grass species. This map provides a foundation for numerous basic and applied investigations including studies of gene organization, gene and genome evolution, targeted cloning, and dissection of complex traits.
Zhang, Deshan; Zhang, Chaochun; Tang, Xiaoyan; Li, Haigang; Zhang, Fusuo; Rengel, Zed; Whalley, William R; Davies, William J; Shen, Jianbo
Root growth is influenced by soil nutrients and neighbouring plants, but how these two drivers affect root interactions and regulate plant growth dynamics is poorly understood. Here, interactions between the roots of maize (Zea mays) and faba bean (Vicia faba) are characterized. Maize was grown alone (maize) or with maize (maize/maize) or faba bean (maize/faba bean) as competitors under five levels of phosphorus (P) supply, and with homogeneous or heterogeneous P distribution. Maize had longer root length and greater shoot biomass and P content when grown with faba bean than with maize. At each P supply rate, faba bean had a smaller root system than maize but greater exudation of citrate and acid phosphatase, suggesting a greater capacity to mobilize P in the rhizosphere. Heterogeneous P availability enhanced the root-length density of maize but not faba bean. Maize root proliferation in the P-rich patches was associated with increased shoot P uptake. Increased P availability by localized P application or by the presence of faba bean exudation stimulated root morphological plasticity and increased shoot growth in maize in the maize/faba bean mixture, suggesting that root interactions of neighbouring plants can be modified by increased P availability.
Chan, Agnes P; Pertea, Geo; Cheung, Foo; Lee, Dan; Zheng, Li; Whitelaw, Cathy; Pontaroli, Ana C; SanMiguel, Phillip; Yuan, Yinan; Bennetzen, Jeffrey; Barbazuk, William Brad; Quackenbush, John; Rabinowicz, Pablo D
Maize is a staple crop of the grass family and also an excellent model for plant genetics. Owing to the large size and repetitiveness of its genome, we previously investigated two approaches to accelerate gene discovery and genome analysis in maize: methylation filtration and high C(0)t selection. These techniques allow the construction of gene-enriched genomic libraries by minimizing repeat sequences due to either their methylation status or their copy number, yielding a 7-fold enrichment in genic sequences relative to a random genomic library. Approximately 900,000 gene-enriched reads from maize were generated and clustered into Assembled Zea mays (AZM) sequences. Here we report the current AZM release, which consists of approximately 298 Mb representing 243,807 sequence assemblies and singletons. In order to provide a repository of publicly available maize genomic sequences, we have created the TIGR Maize Database (http://maize.tigr.org). In this resource, we have assembled and annotated the AZMs and used available sequenced markers to anchor AZMs to maize chromosomes. We have constructed a maize repeat database and generated draft sequence assemblies of 287 maize bacterial artificial chromosome (BAC) clone sequences, which we annotated along with 172 additional publicly available BAC clones. All sequences, assemblies and annotations are available at the project website via web interfaces and FTP downloads.
Singh, Padmanabh; Konar, Arpita; Kumar, Ashish; Srivas, Sweta; Thakur, Mahendra K
The amnesic potential of scopolamine is well manifested through synaptic plasticity gene expression changes and behavioral paradigms of memory impairment. However, the underlying mechanism remains obscure and consequently ideal therapeutic target is lacking. In this context, chromatin-modifying enzymes, which regulate memory gene expression changes, deserve major attention. Therefore, we analyzed the expression of chromatin-modifying enzymes and recovery potential of enzyme modulators in scopolamine-induced amnesia. Scopolamine administration drastically up-regulated DNA methyltransferases (DNMT1) and HDAC2 expression while CREB-binding protein (CBP), DNMT3a and DNMT3b remained unaffected. HDAC inhibitor sodium butyrate and DNMT inhibitor Aza-2'deoxycytidine recovered scopolamine-impaired hippocampal-dependent memory consolidation with concomitant increase in the expression of synaptic plasticity genes Brain-derived neurotrophic factor (BDNF) and Arc and level of histone H3K9 and H3K14 acetylation and decrease in DNA methylation level. Sodium butyrate showed more pronounced effect than Aza-2'deoxycytidine and their co-administration did not exhibit synergistic effect on gene expression. Taken together, we showed for the first time that scopolamine-induced up-regulation of chromatin-modifying enzymes, HDAC2 and DNMT1, leads to gene expression changes and consequent decline in memory consolidation. Our findings on the action of scopolamine as an epigenetic modulator can pave a path for ideal therapeutic targets. We propose the following putative pathway for scopolamine-mediated memory impairment; scopolamine up-regulates hippocampal DNMT1 and HDAC2 expression, induces methylation and deacetylation of BDNF and Arc promoter, represses gene expression and eventually impairs memory consolidation. On the other hand, Aza-2 and NaB inhibit DNMT1 and HDAC2 respectively, up-regulate BDNF and Arc expression and recover memory consolidation. We elucidate the action of
Jokinen, Riikka; Lahtinen, Taina; Marttinen, Paula; Myöhänen, Maarit; Ruotsalainen, Pilvi; Yeung, Nicolas; Shvetsova, Antonina; Kastaniotis, Alexander J.; Hiltunen, J. Kalervo; Öhman, Tiina; Nyman, Tuula A.; Weiler, Hartmut; Battersby, Brendan J.
Mammalian mitochondrial DNA (mtDNA) is a high-copy maternally inherited genome essential for aerobic energy metabolism. Mutations in mtDNA can lead to heteroplasmy, the co-occurence of two different mtDNA variants in the same cell, which can segregate in a tissue-specific manner affecting the onset and severity of mitochondrial dysfunction. To investigate mechanisms regulating mtDNA segregation we use a heteroplasmic mouse model with two polymorphic neutral mtDNA haplotypes (NZB and BALB) that displays tissue-specific and age-dependent selection for mtDNA haplotypes. In the hematopoietic compartment there is selection for the BALB mtDNA haplotype, a phenotype that can be modified by allelic variants of Gimap3. Gimap3 is a tail-anchored member of the GTPase of the immunity-associated protein (Gimap) family of protein scaffolds important for leukocyte development and survival. Here we show how the expression of two murine Gimap3 alleles from Mus musculus domesticus and M. m. castaneus differentially affect mtDNA segregation. The castaneus allele has incorporated a uORF (upstream open reading frame) in-frame with the Gimap3 mRNA that impairs translation and imparts a negative effect on the steady-state protein abundance. We found that quantitative changes in the expression of Gimap3 and the paralogue Gimap5, which encodes a lysosomal protein, affect mtDNA segregation in the mouse hematopoietic tissues. We also show that Gimap3 localizes to the endoplasmic reticulum and not mitochondria as previously reported. Collectively these data show that the abundance of protein scaffolds on the endoplasmic reticulum and lysosomes are important to the segregation of the mitochondrial genome in the mouse hematopoietic compartment. PMID:25808953
Thomas, J. K.; Janz, D. M.
In previous studies we demonstrated that exposure to selenomethionine (SeMet) causes developmental toxicities in zebrafish (Danio rerio). The objectives of this study were to establish a dose-response relationship for developmental toxicities in zebrafish after embryo microinjection of Se (8, 16 or 32 μg/g dry mass of eggs) in the form of SeMet, and to investigate potential underlying mechanism(s) of SeMet-induced developmental toxicities. A dose-dependent increase in frequencies of mortality and total deformities, and reduced hatchability were observed in zebrafish exposed to excess Se via embryo microinjection. The egg Se concentration causing 20% mortality was then used to investigate transcript abundance of proteins involved in antioxidant protection and methylation. Excess Se exposure modified gene expression of oxidant-responsive transcription factors (nuclear factor erythroid 2-related factor nrf2a and nrf2b), and enzymes involved in cellular methylation (methionine adenosyltransferase mat1a and mat2ab) in zebrafish larvae. Notably, excess Se exposure up-regulated transcript abundance of aryl hydrocarbon receptor 2 (ahr2), a signalling pathway involved in the toxicity of dioxin-related compounds. Our findings suggest that oxidative stress or modification of methylation, or a combination of these mechanisms, might be responsible for Se-induced developmental toxicities in fishes. PMID:27210033
Thomas, J. K.; Janz, D. M.
In previous studies we demonstrated that exposure to selenomethionine (SeMet) causes developmental toxicities in zebrafish (Danio rerio). The objectives of this study were to establish a dose-response relationship for developmental toxicities in zebrafish after embryo microinjection of Se (8, 16 or 32 μg/g dry mass of eggs) in the form of SeMet, and to investigate potential underlying mechanism(s) of SeMet-induced developmental toxicities. A dose-dependent increase in frequencies of mortality and total deformities, and reduced hatchability were observed in zebrafish exposed to excess Se via embryo microinjection. The egg Se concentration causing 20% mortality was then used to investigate transcript abundance of proteins involved in antioxidant protection and methylation. Excess Se exposure modified gene expression of oxidant-responsive transcription factors (nuclear factor erythroid 2-related factor nrf2a and nrf2b), and enzymes involved in cellular methylation (methionine adenosyltransferase mat1a and mat2ab) in zebrafish larvae. Notably, excess Se exposure up-regulated transcript abundance of aryl hydrocarbon receptor 2 (ahr2), a signalling pathway involved in the toxicity of dioxin-related compounds. Our findings suggest that oxidative stress or modification of methylation, or a combination of these mechanisms, might be responsible for Se-induced developmental toxicities in fishes.
Verma, Alok Kumar; Kumar, Sandeep; Chaudhari, Bhushan P; Tuteja, Narendra; Das, Mukul; Dwivedi, Premendra D
It is mandatory to assess the allergenic potential of genetically modified (GM) crops before their commercialization. Recently, a transgene [Calcineurin B-like (CBL) protein] has been introduced into tobacco plant to make the crop salt resistance. Therefore, it was felt necessary to assess the allergenic potential of the cbl gene product, which was introduced and expressed in Nicotiana tabacum (tobacco) plant and compared the allergenic effects with the wild-type (WT) counterpart. Bioinformatic analysis revealed that there was no significant sequence homology with known allergens. Also, no difference between the protein digestibility profiles of GM and WT tobacco was found. Rapid digestion of CBL protein (Mol Wt 35 kDa) by simulated gastric fluid (SGF) indicated reduced chances of this protein to induce allergenicity. In addition, BALB/c mice sensitized by intraperitoneal administration of WT and GM tobacco protein showed comparable levels of clinical score, specific IgE, IgG1, histamine level, similar effect on different organs as well as IgE binding proteins. These findings indicate that insertion of cbl gene in tobacco did not cause any additional allergic risk to consumer and the GM and native tobacco proteins behave similarly in both in vitro and in vivo situations even after genetic modification.
MaizeGDB is the maize research community's database for maize genetic and genomic information. In this seminar I will outline our current endeavors including a full website redesign, the status of maize genome assembly and annotation projects, and work toward genome functional annotation. Mechanis...
Pla, Maria; La Paz, José-Luis; Peñas, Gisela; García, Nora; Palaudelmàs, Montserrat; Esteve, Teresa; Messeguer, Joaquima; Melé, Enric
Maize is one of the main crops worldwide and an increasing number of genetically modified (GM) maize varieties are cultivated and commercialized in many countries in parallel to conventional crops. Given the labeling rules established e.g. in the European Union and the necessary coexistence between GM and non-GM crops, it is important to determine the extent of pollen dissemination from transgenic maize to other cultivars under field conditions. The most widely used methods for quantitative detection of GMO are based on real-time PCR, which implies the results are expressed in genome percentages (in contrast to seed or grain percentages). Our objective was to assess the accuracy of real-time PCR based assays to accurately quantify the contents of transgenic grains in non-GM fields in comparison with the real cross-fertilization rate as determined by phenotypical analysis. We performed this study in a region where both GM and conventional maize are normally cultivated and used the predominant transgenic maize Mon810 in combination with a conventional maize variety which displays the characteristic of white grains (therefore allowing cross-pollination quantification as percentage of yellow grains). Our results indicated an excellent correlation between real-time PCR results and number of cross-fertilized grains at Mon810 levels of 0.1-10%. In contrast, Mon810 percentage estimated by weight of grains produced less accurate results. Finally, we present and discuss the pattern of pollen-mediated gene flow from GM to conventional maize in an example case under field conditions.
Sorghum and maize are closely related cereal grains grown throughout the world. Sorghum, a drought tolerant crop grown in semi-arid regions, is a basic food staple in many parts of the developing world, while primarily an animal feed in western countries. Maize, a major worldwide crop, is used for...
This chapter describes the resources held at the Maize Genetics Cooperation • Stock Center in detail and also provides some information about the North Central Regional Plant Introduction Station (NCRPIS) in Ames, IA, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) in Mexico, and the N...
Of the estimated 250-300 races of maize, only 24 races are represented in materials utilized by the Germplasm Enhancement of Maize (GEM) project, a collaborative effort between USDA-ARS and public and private sector research scientists. This is largely a result of poor performance of many races in ...
Xu, Jian-zhong; Zhang, Wei-guo
With the availability of the whole genome sequence of Escherichia coli or Corynebacterium glutamicum, strategies for directed DNA manipulation have developed rapidly. DNA manipulation plays an important role in understanding the function of genes and in constructing novel engineering bacteria according to requirement. DNA manipulation involves modifying the autologous genes and expressing the heterogenous genes. Two alternative approaches, using electroporation linear DNA or recombinant suicide plasmid, allow a wide variety of DNA manipulation. However, the over-expression of the desired gene is generally executed via plasmid-mediation. The current review summarizes the common strategies used for genetically modifying E. coli and C. glutamicum genomes, and discusses the technical problem of multi-layered DNA manipulation. Strategies for gene over-expression via integrating into genome are proposed. This review is intended to be an accessible introduction to DNA manipulation within the bacterial genome for novices and a source of the latest experimental information for experienced investigators. PMID:26834010
Kim, Hyo Jin; Lee, Si Myung; Kim, Jae Kwang; Ryu, Tae Hun; Suh, Seok Cheol; Cho, Hyun Suk
Estimation of the protein levels introduced in a biotechnology-derived product is conducted as part of an overall safety assessment. An enzyme-linked immunosorbent assay (ELISA) was used to analyze phosphinothricin acetyltransferase (PAT) and neomycin phosphotransferase II (NPT II) protein expression in a genetically modified (GM) pepper plant developed in Korea. PAT and NPT II expression levels, based on both dry weight and fresh weight, were variable among different plant generations and plant sections from isolated genetically modified organism (GMO) fields at four developmental stages. PAT expression was highest in leaves at anthesis (11.44 μg/gdw and 2.17 μg/gfw) and lowest in roots (0.12 μg/gdw and 0.01 μg/gfw). NPT II expression was also highest in leaves at anthesis (17.31 μg/gdw and 3.41 μg/gfw) and lowest in red pepper (0.65 μg/gdw and 0.12 μg/gfw). In pollen, PAT expression was 0.59-0.62 μg/gdw, while NPT II was not detected. Both PAT and NPT II showed a general pattern of decreased expression with progression of the growing season. As expected, PAT and NPT II protein expression was not detectable in control pepper plants.
Bernardi, Daniel; Salmeron, Eloisa; Horikoshi, Renato Jun; Bernardi, Oderlei; Dourado, Patrick Marques; Carvalho, Renato Assis; Martinelli, Samuel; Head, Graham P.; Omoto, Celso
Genetically modified plants expressing insecticidal proteins from Bacillus thuringiensis (Bt) offer valuable options for managing insect pests with considerable environmental and economic benefits. Despite the benefits provided by Bt crops, the continuous expression of these insecticidal proteins imposes strong selection for resistance in target pest populations. Bt maize (Zea mays) hybrids have been successful in controlling fall armyworm (Spodoptera frugiperda), the main maize pest in Brazil since 2008; however, field-evolved resistance to the protein Cry1F has recently been reported. Therefore it is important to assess the possibility of cross-resistance between Cry1F and other Cry proteins expressed in Bt maize hybrids. In this study, an F2 screen followed by subsequent selection on MON 89034 maize was used to select an S. frugiperda strain (RR) able to survive on the Bt maize event MON 89034, which expresses the Cry1A.105 and Cry2Ab2 proteins. Field-collected insects from maize expressing the Cry1F protein (event TC1507) represented most of the positive (resistance allele-containing) (iso)families found. The RR strain showed high levels of resistance to Cry1F, which apparently also conferred high levels of cross resistance to Cry1A.105 and Cry1Ab, but had only low-level (10-fold) resistance to Cry2Ab2. Life history studies to investigate fitness costs associated with the resistance in RR strain revealed only small reductions in reproductive rate when compared to susceptible and heterozygous strains, but the RR strain produced 32.2% and 28.4% fewer females from each female relative to the SS and RS (pooled) strains, respectively. Consistent with the lack of significant resistance to Cry2Ab2, MON 89034 maize in combination with appropriate management practices continues to provide effective control of S. frugiperda in Brazil. Nevertheless, the occurrence of Cry1F resistance in S. frugiperda across Brazil, and the cross-resistance to Cry1Ab and Cry1A.105
Han, Shiwen; Zou, Shiying; He, Xiaoyun; Huang, Kunlun; Mei, Xiaohong
The food safety of stacked trait genetically modified (GM) maize GH5112E-117C containing insect-resistance gene Cry1Ah and glyphosate-resistant gene G2-aroA was evaluated in comparison to non-GM Hi-II maize fed to Sprague-Dawley rats during a 90-day subchronic feeding study. Three different dietary concentrations (12.5, 25 and 50 %, w/w) of the GM maize were used or its corresponding non-GM maize. No biologically significant differences in the animals' clinical signs, body weights, food consumption, hematology, clinical chemistry, organ weights and histopathology were found between the stacked trait GM maize groups, and the non-GM maize groups. The results of the 90-day subchronic feeding study demonstrated that the stacked trait GM maize GH5112E-117C is as safe as the conventional non-GM maize Hi-II.
Shephard, Enid; Stutz, Helen; Douglass, Nicola; Mgwebi, Thandi; Meyers, Ann; Chin'ombe, Nyasha; Williamson, Anna-Lise
Numerous features make Mycobacterium bovis BCG an attractive vaccine vector for HIV. It has a good safety profile, it elicits long-lasting cellular immune responses and in addition manufacturing costs are affordable. Despite these advantages it is often difficult to express viral antigens in BCG, which results in genetic instability and low immunogenicity. The aim of this study was to generate stable recombinant BCG (rBCG) that express high levels of HIV antigens, by modification of the HIV genes. A directed evolution process was applied to recombinant mycobacteria that expressed HIV-1 Gag fused to the green fluorescent protein (GFP). Higher growth rates and increased GFP expression were selected for. Through this process a modified Gag antigen was selected. Recombinant BCG that expressed the modified Gag (BCG[pWB106] and BCG[pWB206]) were more stable, produced higher levels of antigen and grew faster than those that expressed the unmodified Gag (BCG[pWB105]). The recombinant BCG that expressed the modified HIV-1 Gag induced 2 to 3 fold higher levels of Gag-specific CD4 T cells than those expressing the unmodified Gag (BCG[pWB105]). Mice primed with 107 CFU BCG[pWB206] and then boosted with MVA-Gag developed Gag-specific CD8 T cells with a frequency of 1343±17 SFU/106 splenocytes, 16 fold greater than the response induced with MVA-Gag alone. Levels of Gag-specific CD4 T cells were approximately 5 fold higher in mice primed with BCG[pWB206] and boosted with MVA-Gag than in those receiving the MVA-Gag boost alone. In addition mice vaccinated with BCG[pWB206] were protected from a surrogate vaccinia virus challenge. PMID:25061753
Lowe, Emily; Truscott, Laurel C.; De Oliveira, Satiro N.
Summary NK cells represent a very promising source for adoptive cellular approaches for cancer immunotherapy, and extensive research has been conducted, including clinical trials. Gene modification of NK cells can direct their specificity and enhance their function, but the efficiency of gene transfer techniques is very limited. Here we describe two protocols designed to generate mature human NK cells from gene-modified hematopoietic stem cells. These protocols use chimeric antigen receptor as the transgene, but could potentially be modified for the expression any particular transgene in human NK cells. PMID:27177671
Beckley, S. A.; Liu, P.; Stover, M. L.; Gunderson, S. I.; Lichtler, A. C.; Rowe, D. W.
Although the primary function of U1 snRNA is to define the 5′ donor site of an intron, it can also block the accumulation of a specific RNA transcript when it binds to a donor sequence within its terminal exon. This work was initiated to investigate if this property of U1 snRNA could be exploited as an effective method for inactivating any target gene. The initial 10-bp segment of U1 snRNA, which is complementary to the 5′ donor sequence, was modified to recognize various target mRNAs (chloramphenicol acetyltransferase [CAT], β-galactosidase, or green fluorescent protein [GFP]). Transient cotransfection of reporter genes and appropriate U1 antitarget vectors resulted in >90% reduction of transgene expression. Numerous sites within the CAT transcript were suitable for targeting. The inhibitory effect of the U1 antitarget vector is directly related to the hybrid formed between the U1 vector and target transcripts and is dependent on an intact 70,000-molecular-weight binding domain within the U1 gene. The effect is long lasting when the target (CAT or GFP) and U1 antitarget construct are inserted into fibroblasts by stable transfection. Clonal cell lines derived from stable transfection with a pOB4GFP target construct and subsequently stably transfected with the U1 anti-GFP construct were selected. The degree to which GFP fluorescence was inhibited by U1 anti-GFP in the various clonal cell lines was assessed by fluorescence-activated cell sorter analysis. RNA analysis demonstrated reduction of the GFP mRNA in the nuclear and cytoplasmic compartment and proper 3′ cleavage of the GFP residual transcript. An RNase protection strategy demonstrated that the transfected U1 antitarget RNA level varied between 1 to 8% of the endogenous U1 snRNA level. U1 antitarget vectors were demonstrated to have potential as effective inhibitors of gene expression in intact cells. PMID:11283260
Morini, Elena; Rizzacasa, Barbara; Pucci, Sabina; Polidoro, Chiara; Ferrè, Fabrizio; Caporossi, Daniela; Helmer Citterich, Manuela; Novelli, Giuseppe; Amati, Francesca
The up-regulation of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), encoded by the OLR1 gene, plays a fundamental role in the pathogenesis of atherosclerosis. Moreover, OLR1 polymorphisms were associated with increased susceptibility to acute myocardial infarction (AMI) and coronary artery diseases (CAD). In these pathologies, the identification of therapeutic approaches that can inhibit or reduce LOX-1 overexpression is crucial. Predictive analysis showed a putative hsa-miR-24 binding site in the 3'UTR of OLR1, 'naturally' mutated by the presence of the rs1050286 single nucleotide polymorphism (SNP). Luciferase assays revealed that miR-24 targets OLR1 3'UTR-G, but not 3'UTR-A (P < 0.0005). The functional relevance of miR-24 in regulating the expression of OLR1 was established by overexpressing miR-24 in human cell lines heterozygous (A/G, HeLa) and homozygous (A/A, HepG2) for rs1050286 SNP. Accordingly, HeLa (A/G), but not HepG2 (A/A), showed a significant down-regulation of OLR1 both at RNA and protein level. Our results indicate that rs1050286 SNP significantly affects miR-24 binding affinity to the 3'UTR of OLR1, causing a more efficient post-transcriptional gene repression in the presence of the G allele. On this basis, we considered that OLR1 rs1050286 SNP may contribute to modify OLR1 susceptibility to AMI and CAD, so ORL1 SNPs screening could help to stratify patients risk.
Fang, Jin; Feng, Yongquan; Zhi, Yuan; Zhang, Lan; Yu, Zhou; Jia, Xudong
GmTMT transgenic maize is a genetically modified maize plant that overexpresses the γ-tocopherol methyltransferase (γ-TMT) from Glycine max (Gm). The γ-TMT gene was introduced into maize line Zhen58 to encode the GmTMT2a protein which can convert γ-tocopherol into α-tocopherol. Overexpression of GmTMT2a significantly increased the α-tocopherol content in transgenic maize. The present study was designed to investigate any potential effects of GmTMT maize grain in a 90-day subchronic rodent feeding study. Maize grains from GmTMT or Zhen58 were incorporated into rodent diets at low (12.5%), medium (25%) or high (50%) concentrations and administered to Sprague-Dawley rats (n = 10/sex/group) for 90 days. The negative control group of rats (n = 10/sex/group) were fed with common maize diets. Results from body weights, feed consumption, clinical chemistry, hematology, absolute and relative organ weights indicated no treatment-related side effects of GmTMT maize grain on rats in comparison with rats consuming diets containing Zhen58 maize grain. In addition, no treatment-related changes were found in necropsy and histopathology examinations. Altogether, our data indicates that GmTMT transgenic maize is as safe and nutritious as its conventional non-transgenic maize.
Yang, Wenxia; Zhang, Yuhong; Zhou, Xiaojin; Zhang, Wei; Xu, Xiaolu; Chen, Rumei; Meng, Qingchang; Yuan, Jianhua; Yang, Peilong; Yao, Bin
Raffinose-family oligosaccharide (RFO) in soybeans is one of the major anti-nutritional factors for poultry and livestocks. α-Galactosidase is commonly supplemented into the animal feed to hydrolyze α-1,6-galactosidic bonds on the RFOs. To simplify the feed processing, a protease-resistant α-galactosidase encoding gene from Gibberella sp. strain F75, aga-F75, was modified by codon optimization and heterologously expressed in the embryos of transgentic maize driven by the embryo-specific promoter ZM-leg1A. The progenies were produced by backcrossing with the commercial inbred variety Zheng58. PCR, southern blot and western blot analysis confirmed the stable integration and tissue specific expression of the modified gene, aga-F75m, in seeds over four generations. The expression level of Aga-F75M reached up to 10,000 units per kilogram of maize seeds. In comparison with its counterpart produced in Pichia pastoris strain GS115, maize seed-derived Aga-F75M showed a lower temperature optimum (50 °C) and lower stability over alkaline pH range, but better thermal stability at 60 °C to 70 °C and resistance to feed pelleting inactivation (80 °C). This is the first report of producing α-galactosidase in transgenic plant. The study offers an effective and economic approach for direct utilization of α-galactosidase-producing maize without any purification or supplementation procedures in the feed processing.
Xuan, Ning; Zhao, Chuanzhi; Peng, Zhenying; Chen, Gao; Bian, Fei; Lian, Mingzheng; Liu, Guoxia; Wang, Xingjun; Bi, Yuping
Maize is one of the most important food crops. Rice black-streaked dwarf virus is a maize rough dwarf disease pathogen. The occurrence and transmission of maize rough dwarf disease brings great damage to maize production. The technology of using artificial miRNA to build antiviral plant has been proven effective in a variety of plants. However, such trials in maize have not been reported. We designed primers based on the sequence of maize zea-miR159a precursor and sequence of function protein genes and silencing RBSDV coding genes in RBSDV genome. We constructed amiRNA (artificial miRNA) gene for silencing RBSDV coding gene and gene silencing suppressor. We constructed pCAMBIA3301-121-amiRNA plant expression vector for transforming maize inbred lines Z31 by using agrobacterium mediated method. After molecular analysis of transgenic maize, homozygous lines with high miRNA expression were selected by molecular detection for a subsequent natural infection experiment. We studied the severity of maize rough dwarf disease according to a grading standard (grade 0 to 4). The experiment results showed that the disease resistance of transgenic homozygous maize with the anti-rough dwarf virus amiRNA vector was better than that of wild type. Among the transgenic maize, S6-miR159 transgenic maize had high disease resistance. It is feasible to create new maize variety by the use of artificial miRNA.
O'Callaghan, Maureen; Brownbridge, Michael; Stilwell, Wendy B; Gerard, Emily M; Burgess, Elisabeth P J; Barraclough, Emma I; Christeller, John T
Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin inhibitor (BSTI) were examined in laboratory assays against three earthworm and one collembolan species. BSTI is a serine protease inhibitor that can bind to the digestive trypsins of insects feeding on modified plants, resulting in reduced growth and survival. Protease inhibitors are active against a broad range of insects, so may have a large impact on non-target organisms. Survival and fecundity of the collembolan Folsomia candida were unaffected by consumption of artificial diet containing BSTI-expressing tobacco leaf or powdered freeze-dried BSTI-expressing tobacco leaf that was added to soil. Similarly, mortality and growth of earthworms Aporrectodea caliginosa and Lumbricus rubellus did not differ significantly between soil augmented with BSTI-expressing tobacco leaves or unmodified control leaves. The redworm Eisenia fetida gained less weight when provided with BSTI-expressing leaves in one assay, but when the experiment was repeated, there was no significant difference between treatments. BSTI-expressing tobacco and unmodified control leaves decomposed at the same rate, indicating that the inhibitor had no effect on the overall function of the decomposer community of micro-flora and fauna in soil.
Vermaas, Willem F J.
Disclosed is a modified photoautotrophic bacterium comprising genes of interest that are modified in terms of their expression and/or coding region sequence, wherein modification of the genes of interest increases production of a desired product in the bacterium relative to the amount of the desired product production in a photoautotrophic bacterium that is not modified with respect to the genes of interest.
Cell Type-Specific Gene Expression Analyses by RNA Sequencing Reveal Local High Nitrate-Triggered Lateral Root Initiation in Shoot-Borne Roots of Maize by Modulating Auxin-Related Cell Cycle Regulation1[OPEN
Yu, Peng; Eggert, Kai; von Wirén, Nicolaus; Li, Chunjian; Hochholdinger, Frank
Plants have evolved a unique plasticity of their root system architecture to flexibly exploit heterogeneously distributed mineral elements from soil. Local high concentrations of nitrate trigger lateral root initiation in adult shoot-borne roots of maize (Zea mays) by increasing the frequency of early divisions of phloem pole pericycle cells. Gene expression profiling revealed that, within 12 h of local high nitrate induction, cell cycle activators (cyclin-dependent kinases and cyclin B) were up-regulated, whereas repressors (Kip-related proteins) were down-regulated in the pericycle of shoot-borne roots. In parallel, a ubiquitin protein ligase S-Phase Kinase-Associated Protein1-cullin-F-box proteinS-Phase Kinase-Associated Protein 2B-related proteasome pathway participated in cell cycle control. The division of pericycle cells was preceded by increased levels of free indole-3-acetic acid in the stele, resulting in DR5-red fluorescent protein-marked auxin response maxima at the phloem poles. Moreover, laser-capture microdissection-based gene expression analyses indicated that, at the same time, a significant local high nitrate induction of the monocot-specific PIN-FORMED9 gene in phloem pole cells modulated auxin efflux to pericycle cells. Time-dependent gene expression analysis further indicated that local high nitrate availability resulted in PIN-FORMED9-mediated auxin efflux and subsequent cell cycle activation, which culminated in the initiation of lateral root primordia. This study provides unique insights into how adult maize roots translate information on heterogeneous nutrient availability into targeted root developmental responses. PMID:26198256
Cell Type-Specific Gene Expression Analyses by RNA Sequencing Reveal Local High Nitrate-Triggered Lateral Root Initiation in Shoot-Borne Roots of Maize by Modulating Auxin-Related Cell Cycle Regulation.
Yu, Peng; Eggert, Kai; von Wirén, Nicolaus; Li, Chunjian; Hochholdinger, Frank
Plants have evolved a unique plasticity of their root system architecture to flexibly exploit heterogeneously distributed mineral elements from soil. Local high concentrations of nitrate trigger lateral root initiation in adult shoot-borne roots of maize (Zea mays) by increasing the frequency of early divisions of phloem pole pericycle cells. Gene expression profiling revealed that, within 12 h of local high nitrate induction, cell cycle activators (cyclin-dependent kinases and cyclin B) were up-regulated, whereas repressors (Kip-related proteins) were down-regulated in the pericycle of shoot-borne roots. In parallel, a ubiquitin protein ligase S-Phase Kinase-Associated Protein1-cullin-F-box protein(S-Phase Kinase-Associated Protein 2B)-related proteasome pathway participated in cell cycle control. The division of pericycle cells was preceded by increased levels of free indole-3-acetic acid in the stele, resulting in DR5-red fluorescent protein-marked auxin response maxima at the phloem poles. Moreover, laser-capture microdissection-based gene expression analyses indicated that, at the same time, a significant local high nitrate induction of the monocot-specific PIN-FORMED9 gene in phloem pole cells modulated auxin efflux to pericycle cells. Time-dependent gene expression analysis further indicated that local high nitrate availability resulted in PIN-FORMED9-mediated auxin efflux and subsequent cell cycle activation, which culminated in the initiation of lateral root primordia. This study provides unique insights into how adult maize roots translate information on heterogeneous nutrient availability into targeted root developmental responses.
Schnable, James C; Freeling, Michael
Not all genes are created equal. Despite being supported by sequence conservation and expression data, knockout homozygotes of many genes show no visible effects, at least under laboratory conditions. We have identified a set of maize (Zea mays L.) genes which have been the subject of a disproportionate share of publications recorded at MaizeGDB. We manually anchored these "classical" maize genes to gene models in the B73 reference genome, and identified syntenic orthologs in other grass genomes. In addition to proofing the most recent version 2 maize gene models, we show that a subset of these genes, those that were identified by morphological phenotype prior to cloning, are retained at syntenic locations throughout the grasses at much higher levels than the average expressed maize gene, and are preferentially found on the maize1 subgenome even with a duplicate copy is still retained on the opposite subgenome. Maize1 is the subgenome that experienced less gene loss following the whole genome duplication in maize lineage 5-12 million years ago and genes located on this subgenome tend to be expressed at higher levels in modern maize. Links to the web based software that supported our syntenic analyses in the grasses should empower further research and support teaching involving the history of maize genetic research. Our findings exemplify the concept of "grasses as a single genetic system," where what is learned in one grass may be applied to another.
Iuchi, Katsuya; Imoto, Akemi; Kamimura, Naomi; Nishimaki, Kiyomi; Ichimiya, Harumi; Yokota, Takashi; Ohta, Shigeo
We previously showed that H2 acts as a novel antioxidant to protect cells against oxidative stress. Subsequently, numerous studies have indicated the potential applications of H2 in therapeutic and preventive medicine. Moreover, H2 regulates various signal transduction pathways and the expression of many genes. However, the primary targets of H2 in the signal transduction pathways are unknown. Here, we attempted to determine how H2 regulates gene expression. In a pure chemical system, H2 gas (approximately 1%, v/v) suppressed the autoxidation of linoleic acid that proceeds by a free radical chain reaction, and pure 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine (PAPC), one of the major phospholipids, was autoxidized in the presence or absence of H2. H2 modified the chemical production of the autoxidized phospholipid species in the cell-free system. Exposure of cultured cells to the H2-dependently autoxidized phospholipid species reduced Ca2+ signal transduction and mediated the expression of various genes as revealed by comprehensive microarray analysis. In the cultured cells, H2 suppressed free radical chain reaction-dependent peroxidation and recovered the increased cellular Ca2+, resulting in the regulation of Ca2+-dependent gene expression. Thus, H2 might regulate gene expression via the Ca2+ signal transduction pathway by modifying the free radical-dependent generation of oxidized phospholipid mediators. PMID:26739257
Chen, Qiang; Zhong, Hao; Fan, Xian-Wei; Li, You-Zhi
Response of maize to photoperiods affects adaption of this crop to environments. We characterize the phenotypes of four temperate-adapted maize foundation parents, Huangzao 4, Chang 7-2, Ye 478 and Zheng 58, and two tropically adapted maize foundation parents, M9 and Shuang M9 throughout the growth stage under three constant photoperiod regimes in a daily cycle of 24 h at 28 °C, and analysed expression of 48 photoperiod response-associated genes. Consequently, long photoperiod (LP) repressed development of the tassels of photoperiod-sensitive maize lines at V9 stage, and caused subsequent failure in flowering; failure of photoperiod-sensitive maize lines in flowering under LP was associated with lower expression of flowering-related genes; photoperiod changes could make a marked impact on spatial layout of maize inflorescence. The larger oscillation amplitude of expression of photoperiod-responsive genes occurred in LP-sensitive maize lines. In conclusion, failure in development of tassels at V9 stage under LP is an early indicator for judging photoperiod sensitivity. The adaptation of temperate-adapted maize lines to LP is due to the better coordination of expression among photoperiod-sensing genes instead of the loss of the genes. High photoperiod sensitivity of maize is due to high expression of circadian rhythm-responding genes improperly early in the light.
Song, Y E; Wang, X; Shen, Z W; Xu, Y; Li, J Y
The colour of red, purple, brown and white occurs in pericarp of rice. Here, the maize anthocyanin regulatory gene Lc under control of the promoter of the rice glutelin gene Gt1 was introduced in the white pericarp rice "Chao2-10" and purple pericarp rice "Qingjiaozidao". The results demonstrated that some transgenic "Chao2-10" rice pericarps became brown, and the total flavonoid contents in the unpolished rice of the two transgenic rices increased significantly compared with their respective controls. Unpolished rice kernel thickness and weight in the two transgenic rices decreased slightly.
Frame, Bronwyn; Warnberg, Katey; Main, Marcy; Wang, Kan
Agrobacterium tumefaciens-mediated transformation is an effective method for introducing genes into maize. In this chapter, we describe a detailed protocol for genetic transformation of the maize genotype Hi II. Our starting plant material is immature embryos cocultivated with an Agrobacterium strain carrying a standard binary vector. In addition to step-by-step laboratory transformation procedures, we include extensive details in growing donor plants and caring for transgenic plants in the greenhouse.
Adel-Patient, Karine; Guimaraes, Valeria D; Paris, Alain; Drumare, Marie-Françoise; Ah-Leung, Sandrine; Lamourette, Patricia; Nevers, Marie-Claire; Canlet, Cécile; Molina, Jérôme; Bernard, Hervé; Créminon, Christophe; Wal, Jean-Michel
We have investigated the immunological and metabolomic impacts of Cry1Ab administration to mice, either as a purified protein or as the Cry1Ab-expressing genetically modified (GM) MON810 maize. Humoral and cellular specific immune responses induced in BALB/cJ mice after intra-gastric (i.g.) or intra-peritoneal (i.p.) administration of purified Cry1Ab were analyzed and compared with those induced by proteins of various immunogenic and allergic potencies. Possible unintended effects of the genetic modification on the pattern of expression of maize natural allergens were studied using IgE-immunoblot and sera from maize-allergic patients. Mice were experimentally sensitized (i.g. or i.p. route) with protein extracts from GM or non-GM maize, and then anti-maize proteins and anti-Cry1Ab-induced immune responses were analyzed. In parallel, longitudinal metabolomic studies were performed on the urine of mice treated via the i.g. route. Weak immune responses were observed after i.g. administration of the different proteins. Using the i.p. route, a clear Th2 response was observed with the known allergenic proteins, whereas a mixed Th1/Th2 immune response was observed with immunogenic protein not known to be allergenic and with Cry1Ab. This then reflects protein immunogenicity in the BALB/c Th2-biased mouse strain rather than allergenicity. No difference in natural maize allergen profiles was evidenced between MON810 and its non-GM comparator. Immune responses against maize proteins were quantitatively equivalent in mice treated with MON810 vs the non-GM counterpart and no anti-Cry1Ab-specific immune response was detected in mice that received MON810. Metabolomic studies showed a slight "cultivar" effect, which represented less than 1% of the initial metabolic information. Our results confirm the immunogenicity of purified Cry1Ab without evidence of allergenic potential. Immunological and metabolomic studies revealed slight differences in mouse metabolic profiles after i
Adel-Patient, Karine; Guimaraes, Valeria D.; Paris, Alain; Drumare, Marie-Françoise; Ah-Leung, Sandrine; Lamourette, Patricia; Nevers, Marie-Claire; Canlet, Cécile; Molina, Jérôme; Bernard, Hervé; Créminon, Christophe; Wal, Jean-Michel
We have investigated the immunological and metabolomic impacts of Cry1Ab administration to mice, either as a purified protein or as the Cry1Ab-expressing genetically modified (GM) MON810 maize. Humoral and cellular specific immune responses induced in BALB/cJ mice after intra-gastric (i.g.) or intra-peritoneal (i.p.) administration of purified Cry1Ab were analyzed and compared with those induced by proteins of various immunogenic and allergic potencies. Possible unintended effects of the genetic modification on the pattern of expression of maize natural allergens were studied using IgE-immunoblot and sera from maize-allergic patients. Mice were experimentally sensitized (i.g. or i.p. route) with protein extracts from GM or non-GM maize, and then anti-maize proteins and anti-Cry1Ab–induced immune responses were analyzed. In parallel, longitudinal metabolomic studies were performed on the urine of mice treated via the i.g. route. Weak immune responses were observed after i.g. administration of the different proteins. Using the i.p. route, a clear Th2 response was observed with the known allergenic proteins, whereas a mixed Th1/Th2 immune response was observed with immunogenic protein not known to be allergenic and with Cry1Ab. This then reflects protein immunogenicity in the BALB/c Th2-biased mouse strain rather than allergenicity. No difference in natural maize allergen profiles was evidenced between MON810 and its non-GM comparator. Immune responses against maize proteins were quantitatively equivalent in mice treated with MON810 vs the non-GM counterpart and no anti-Cry1Ab–specific immune response was detected in mice that received MON810. Metabolomic studies showed a slight “cultivar” effect, which represented less than 1% of the initial metabolic information. Our results confirm the immunogenicity of purified Cry1Ab without evidence of allergenic potential. Immunological and metabolomic studies revealed slight differences in mouse metabolic profiles
Lu, Jiamiao; Zhang, Feijie; Fire, Andrew Z; Kay, Mark A
Conventional plasmid vectors are incapable of achieving sustained levels of transgene expression in vivo even in quiescent mammalian tissues because the transgene expression cassette is silenced. Transcriptional silencing results from the presence of the bacterial plasmid backbone or virtually any DNA sequence of >1 kb in length placed outside of the expression cassette. Here, we show that transcriptional silencing can be substantially forestalled by increasing the An/Tn sequence composition in the plasmid bacterial backbone. Increasing numbers of An/Tn sequences increased sustained transcription of both backbone sequences and adjacent expression cassettes. In order to recapitulate these expression profiles in compact and portable plasmid DNA backbones, we engineered the standard kanamycin or ampicillin antibiotic resistance genes, optimizing the number of An/Tn sequence without altering the encoded amino acids. The resulting vector backbones yield sustained transgene expression from mouse liver, providing generic DNA vectors capable of sustained transgene expression without additional genes or mammalian regulatory elements.
Easton, D F; Ponder, M A; Huson, S M; Ponder, B A
Neurofibromatosis (NF) type 1 (NF1) is notable for its variable expression. To determine whether variation in expression has an inherited component, we examined 175 individuals in 48 NF families, including six MZ twin pairs. Three quantitative traits were scored--number of café-au-lait patches, number of cutaneous neurofibromas, and head circumference; and five binary traits were scored--the presence or absence of plexiform neurofibromas, optic gliomas, scoliosis, epilepsy, and referral for remedial education. For café-au-lait patches and neurofibromas, correlation was highest between MZ twins, less high between first-degree relatives, and lower still between more distant relatives. The high correlation between MZ twins suggests a strong genetic component in variation of expression, but the low correlation between distant relatives suggests that the type of mutation at the NF1 locus itself plays only a minor role. All of the five binary traits, with the exception of plexiform neurofibromas, also showed significant familial clustering. The familial effects for these traits were consistent with polygenic effects, but there were insufficient data to rule out other models, including a significant effect of different NF1 mutations. There was no evidence of any association between the different traits in affected individuals. We conclude that the phenotypic expression of NF1 is to a large extent determined by the genotype at other "modifying" loci and that these modifying genes are trait specific. PMID:8328449
Su, Chun-Lin; Chen, Wan-Chieh; Lee, Ann-Ying; Chen, Chun-Yi; Chang, Yao-Chien Alex; Chao, Ya-Ting; Shih, Ming-Che
Previously we developed genomic resources for orchids, including transcriptomic analyses using next-generation sequencing techniques and construction of a web-based orchid genomic database. Here, we report a modified molecular model of flower development in the Orchidaceae based on functional analysis of gene expression profiles in Phalaenopsis aphrodite (a moth orchid) that revealed novel roles for the transcription factors involved in floral organ pattern formation. Phalaenopsis orchid floral organ-specific genes were identified by microarray analysis. Several critical transcription factors including AP3, PI, AP1 and AGL6, displayed distinct spatial distribution patterns. Phylogenetic analysis of orchid MADS box genes was conducted to infer the evolutionary relationship among floral organ-specific genes. The results suggest that gene duplication MADS box genes in orchid may have resulted in their gaining novel functions during evolution. Based on these analyses, a modified model of orchid flowering was proposed. Comparison of the expression profiles of flowers of a peloric mutant and wild-type Phalaenopsis orchid further identified genes associated with lip morphology and peloric effects. Large scale investigation of gene expression profiles revealed that homeotic genes from the ABCDE model of flower development classes A and B in the Phalaenopsis orchid have novel functions due to evolutionary diversification, and display differential expression patterns.
Sanvido, Olivier; Widmer, Franco; Winzeler, Michael; Streit, Bernhard; Szerencsits, Erich; Bigler, Franz
A major concern related to the adoption of genetically modified (GM) crops in agricultural systems is the possibility of unwanted GM inputs into non-GM crop production systems. Given the increasing commercial cultivation of GM crops in the European Union (EU), there is an urgent need to define measures to prevent mixing of GM with non-GM products during crop production. Cross-fertilization is one of the various mechanisms that could lead to GM-inputs into non-GM crop systems. Isolation distances between GM and non-GM fields are widely accepted to be an effective measure to reduce these inputs. However, the question of adequate isolation distances between GM and non-GM maize is still subject of controversy both amongst scientists and regulators. As several European countries have proposed largely differing isolation distances for maize ranging from 25 to 800 m, there is a need for scientific criteria when using cross-fertilization data of maize to define isolation distances between GM and non-GM maize. We have reviewed existing cross-fertilization studies in maize, established relevant criteria for the evaluation of these studies and applied these criteria to define science-based isolation distances. To keep GM-inputs in the final product well below the 0.9% threshold defined by the EU, isolation distances of 20 m for silage and 50 m for grain maize, respectively, are proposed. An evaluation using statistical data on maize acreage and an aerial photographs assessment of a typical agricultural landscape by means of Geographic Information Systems (GIS) showed that spatial resources would allow applying the defined isolation distances for the cultivation of GM maize in the majority of the cases under actual Swiss agricultural conditions. The here developed approach, using defined criteria to consider the agricultural context of maize cultivation, may be of assistance for the analysis of cross-fertilization data in other countries.
Loza-Tavera, Herminia; Martínez-Barajas, Eleazar; Sánchez-de-Jiménez, Estela
Ribulose-1,5-bisphosphate carboxylase oxygenase (EC 18.104.22.168) (Rubisco) activity, Rubisco-protein, and Rubisco large and small subunit gene (rbcL and rbcS) transcripts were measured at seven stages of development in the second leaf of maize (Zea mays L.) seedlings belonging to low and high yield populations. During the three early stages of development, when the leaf has not yet expanded, it was determined that increments in Rubisco-activity were caused by increases in Rubisco-protein and its mRNAs. Afterward, the rbcS level decreased sharply down to nondetectable levels at the seventh stage, when the leaf was at the beginning of senescence. As a contrast, rbcL transcript decreased slowly and Rubisco-protein accumulated up to the fifth stage, when the leaf reached its maximum expansion. A slight decrease in Rubisco-protein was then observed. These results suggest that at early stages of development Rubisco-activity and Rubisco-protein are regulated mainly at the transcriptional level. At the later phase the regulation seems to be at other biochemical levels. Neither Rubisco activity nor Rubisco-protein showed correlation with yield for both maize populations at this stage of development. Slightly higher levels of both transcripts were observed in the high yield population. Images Figure 1 Figure 6 PMID:16667500
Kanno, Akira; Saeki, Hiroshi; Kameya, Toshiaki; Saedler, Heinz; Theissen, Günter
In higher eudicotyledonous angiosperms the floral organs are typically arranged in four different whorls, containing sepals, petals, stamens and carpels. According to the ABC model, the identity of these organs is specified by floral homeotic genes of class A, A+B, B+C and C, respectively. In contrast to the sepal and petal whorls of eudicots, the perianths of many plants from the Liliaceae family have two outer whorls of almost identical petaloid organs, called tepals. To explain the Liliaceae flower morphology, van Tunen et al. (1993) proposed a modified ABC model, exemplified with tulip. According to this model, class B genes are not only expressed in whorls 2 and 3, but also in whorl 1. Thus the organs of both whorls 1 and 2 express class A plus class B genes and, therefore, get the same petaloid identity. To test this modified ABC model we have cloned and characterized putative class B genes from tulip. Two DEF- and one GLO-like gene were identified, named TGDEFA, TGDEFB and TGGLO. Northern hybridization analysis showed that all of these genes are expressed in whorls 1, 2 and 3 (outer and inner tepals and stamens), thus corroborating the modified ABC model. In addition, these experiments demonstrated that TGGLO is also weakly expressed in carpels, leaves, stems and bracts. Gel retardation assays revealed that TGGLO alone binds to DNA as a homodimer. In contrast, TGDEFA and TGDEFB cannot homodimerize, but make heterodimers with PI. Homodimerization of GLO-like protein has also been reported for lily, suggesting that this phenomenon is conserved within Liliaceae plants or even monocot species.
Manzanares, Paloma; Orejas, Margarita; Gil, José Vicente; de Graaff, Leo H.; Visser, Jaap; Ramón, Daniel
The Aspergillus aculeatus rhaA gene encoding an α-l-rhamnosidase has been expressed in both laboratory and industrial wine yeast strains. Wines produced in microvinifications, conducted using a combination of the genetically modified industrial strain expressing rhaA and another strain expressing a β-glucosidase, show increased content mainly of the aromatic compound linalool. PMID:14660415
Sadio, Ana; Gustafsson, Jenny K.; Pereira, Bruno; Gomes, Carla Pereira; Hansson, Gunnar C.; David, Leonor; Pêgo, Ana Paula; Almeida, Raquel
Development of effective non-viral vectors is of crucial importance in the implementation of RNA interference in clinical routine. The localized delivery of siRNAs to the gastrointestinal mucosa is highly desired but faces specific problems such as the stability in gastric acidity conditions and the presence of the mucus barrier. CDX2 is a transcription factor critical for intestinal differentiation being involved in the initiation and maintenance of gastrointestinal diseases. Specifically, it is the trigger of gastric intestinal metaplasia which is a precursor lesion of gastric cancer. Its expression is also altered in colorectal cancer, where it may constitute a lineage-survival oncogene. Our main objective was to develop a nanoparticle-delivery system of siRNA targeting CDX2 using modified chitosan as a vector. CDX2 expression was assessed in gastric carcinoma cell lines and nanoparticles behaviour in gastrointestinal mucus was tested in mouse explants. We show that imidazole-modified chitosan and trimethylchitosan/siRNA nanoparticles are able to downregulate CDX2 expression and overpass the gastric mucus layer but not colonic mucus. This system might constitute a potential therapeutic approach to treat CDX2-dependent gastric lesions. PMID:24925340
Yang, Jianbo; Price, Matthew A.; Li, GuiYuan; Bar-Eli, Menashe; Salgia, Ravi; Jagedeeswaran, Ramasamy; Carlson, Jennifer H.; Ferrone, Soldano; Turley, Eva A.; McCarthy, James B.
Melanoma chondroitin sulfate proteoglycan (MCSP) is a plasma membrane-associated proteoglycan that facilitates the growth, motility and invasion of tumor cells. MCSP expression in melanoma cells enhances integrin function and constitutive activation of Erk 1,2. The current studies were performed to determine the mechanism by which MCSP expression promotes tumor growth and motility. The results demonstrate that MCSP expression in radial growth phase (RGP), vertical growth phase (VGP) or metastatic cell lines causes sustained activation of Erk 1,2, enhanced growth and motility which all require the cytoplasmic domain of the MCSP core protein. MCSP expression in an RGP cell line also promotes an epithelial to mesenchymal transition (EMT) based on changes in cell morphology and the expression of several EMT markers. Finally MCSP enhances the expression of c-Met and HGF, and inhibiting c-Met expression or activation limits the increased growth and motility of multiple melanoma cell lines. The studies collectively demonstrate an importance for MCSP in promoting progression by an epigenetic mechanism and they indicate that MCSP could be targeted to delay or inhibit tumor progression in patients. PMID:19738072
Anderson, D W; Mettil, W A; Schneider, J S
Developmental lead (Pb) exposure impairs various cognitive processes and behaviors in both humans and animals. In particular, specific deficits in spatial learning and memory have been described in Pb-exposed rats. It is also known that rearing environment (i.e., non-enriched vs. enriched) can have significant influences on cognitive performance and that rearing environment and sex may modify the influence of Pb exposure on learning and memory processes. It is also known that behavioral testing can alter hippocampal gene expression and interactive effects of environment. Little is known however about the molecular correlates of developmental Pb-exposure on expression of key sets of cognition-relevant genes in the hippocampus and how sex and environmental rearing condition may modify these effects. The present study examined expression profiles of neurobiologically-relevant genes (i.e., neurotrophic factors, NMDA receptors, metabotropic glutamate receptors, synaptic function/plasticity, and transcription/gene regulation) in behaviorally naïve rats with perinatal exposure (i.e., gestation through weaning) to different levels of Pb (250, 750 and 1,500 ppm Pb acetate) in males and females raised in a non-enriched environment (standard housing without toys) or an enriched environment (large cage containing toys changed twice weekly). Unlike previous studies identifying gene changes following behavioral testing, which alters expression analysis, we identified both sex and environmental related changes in hippocampal genes following Pb exposure alone. The gene expression changes described may be associated with learning and memory and may pre-determine how cognitive profiles develop following Pb exposure.
Cai, Demin; Jia, Yimin; Lu, Jingyu; Yuan, Mengjie; Sui, Shiyan; Song, Haogang; Zhao, Ruqian
To elucidate the effects of maternal dietary betaine supplementation on hepatic expression of cholesterol metabolic genes in newborn piglets and the involved epigenetic mechanisms, we fed gestational sows with control or betaine-supplemented diets (3 g/kg) throughout pregnancy. Neonatal piglets born to betaine-supplemented sows had higher serum methionine concentration and hepatic content of betaine, which was associated with significantly up-regulated hepatic expression of glycine N-methyltransferase. Prenatal betaine exposure increased hepatic cholesterol content and modified the hepatic expression of cholesterol metabolic genes in neonatal piglets. Sterol regulatory element-binding protein 2 was down-regulated at both mRNA and protein levels, while 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR) was down-regulated at the mRNA level, but up-regulated at the protein level, in betaine-exposed piglets. The transcriptional repression of HMGCR was associated with CpG island hypermethylation and higher repressive histone mark H3K27me3 (histone H3 lysine 27 trimethylation) on the promoter, whereas increased HMGCR protein content was associated with significantly decreased expression of miR-497. Furthermore, LDL receptor was significantly down-regulated at both mRNA and protein levels in the liver of betaine-exposed piglets, which was associated with promoter CpG hypermethylation. In addition, the expression of cholesterol-27α-hydroxylase (CYP27α1) was up-regulated at both mRNA and protein levels, while the expression of cholesterol-7α-hydroxylase (CYP7α1) was increased at the mRNA level, but unchanged at the protein level associated with increased expression of miR-181. These results indicate that maternal betaine supplementation increases hepatic cholesterol content in neonatal piglets through epigenetic regulations of cholesterol metabolic genes, which involve alterations in DNA and histone methylation and in the expression of microRNA targeting these genes.
Ahmad, Rafiq; Zuily-Fodil, Yasmine; Passaquet, Chantal; Bethenod, Olivier; Roche, Romain; Repellin, Anne
Maize plants (Zea mays L. cv. NK Perform) were exposed to O(3)-enriched air, using a new field fumigation system. Transcriptional changes for three type II-metacaspase genes were studied in the leaves (ranks 10 and 12), using quantitative real-time PCR. Global metacaspase activity was measured using metacaspase-specific synthetic tripeptide Boc-GRR-AMC. Aging had little effect on mRNA accumulation whereas four to six-fold increases were observed for the most O(3)-responsive type II metacaspase genes, in the older leaves 10. Global metacaspase activity increased by 257% and 333% in leaves 12 and 10, respectively, in response to the highest cumulated concentration. In non-fumigated plants, metacaspase activity progressively increased over the course of the experiment and always was higher in the older leaves 10. Together, these results suggest that metacaspase-mediated proteolysis is a crucial step in leaf responses to both O(3) and age-mediated senescence.
Cherubini, Emanuela; Tabbì, Luca; Scozzi, Davide; Mariotta, Salvatore; Galli, Elena; Carello, Rossella; Avitabile, Simona; Tayebati, Seyed Koshrow; Amenta, Francesco; De Vitis, Claudia; Mancini, Rita; Ricci, Alberto
Lymphocytes possess an independent cholinergic system. We assessed the expression of muscarinic cholinergic receptors in lymphocytes from 49 asthmatic children and 10 age matched controls using Western blot. We demonstrated that CD4+ and CD8+ T cells expressed M2 and M4 muscarinic receptors which density were significantly increased in asthmatic children in comparison with controls. M2 and M4 receptor increase was strictly related with IgE and fraction of exhaled nitric oxide (FeNO) measurements and with impairment in objective measurements of airway obstruction. Increased lymphocyte muscarinic cholinergic receptor expression may concur with lung cholinergic dysfunction and with inflammatory molecular framework in asthma.
Lemmon, Zachary H.; Bukowski, Robert; Sun, Qi; Doebley, John F.
Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem). Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes) show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues. PMID:25375861
Genotypical Differences in Aluminum Resistance of Maize Are Expressed in the Distal Part of the Transition Zone. Is Reduced Basipetal Auxin Flow Involved in Inhibition of Root Elongation by Aluminum?1
Kollmeier, Malte; Felle, Hubert H.; Horst, Walter J.
Short-term Al treatment (90 μm Al at pH 4.5 for 1 h) of the distal transition zone (DTZ; 1–2 mm from the root tip), which does not contribute significantly to root elongation, inhibited root elongation in the main elongation zone (EZ; 2.5–5 mm from the root tip) to the same extent as treatment of the entire maize (Zea mays) root apex. Application of Al to the EZ had no effect on root elongation. Higher genotypical resistance to Al applied to the entire root apex, and specifically to the DTZ, was expressed by less inhibition of root elongation, Al accumulation, and Al-induced callose formation, primarily in the DTZ. A characteristic pH profile along the surface of the root apex with a maximum of pH 5.3 in the DTZ was demonstrated. Al application induced a substantial flattening of the pH profile moreso in the Al-sensitive than in the Al-resistant cultivar. Application of indole-3-acetic acid to the EZ but not to the meristematic zone significantly alleviated the inhibition of root elongation induced by the application of Al to the DTZ. Basipetal transport of exogenously applied [3H]indole-3-acetic acid to the meristematic zone was significantly inhibited by Al application to the DTZ in the Al-sensitive maize cv Lixis. Our results provide evidence that the primary mechanisms of genotypical differences in Al resistance are located within the DTZ, and suggest a signaling pathway in the root apex mediating the Al signal between the DTZ and the EZ through basipetal auxin transport. PMID:10712559
Bähr, Andrea; Käser, Tobias; Kemter, Elisabeth; Gerner, Wilhelm; Kurome, Mayuko; Baars, Wiebke; Herbach, Nadja; Witter, Kirsti; Wünsch, Annegret; Talker, Stephanie C; Kessler, Barbara; Nagashima, Hiroshi; Saalmüller, Armin; Schwinzer, Reinhard; Wolf, Eckhard; Klymiuk, Nikolai
We have successfully established and characterized a genetically modified pig line with ubiquitous expression of LEA29Y, a human CTLA4-Ig derivate. LEA29Y binds human B7.1/CD80 and B7.2/CD86 with high affinity and is thus a potent inhibitor of T cell co-stimulation via this pathway. We have characterized the expression pattern and the biological function of the transgene as well as its impact on the porcine immune system and have evaluated the potential of these transgenic pigs to propagate via assisted breeding methods. The analysis of LEA29Y expression in serum and multiple organs of CAG-LEA transgenic pigs revealed that these animals produce a biologically active transgenic product at a considerable level. They present with an immune system affected by transgene expression, but can be maintained until sexual maturity and propagated by assisted reproduction techniques. Based on previous experience with pancreatic islets expressing LEA29Y, tissues from CAG-LEA29Y transgenic pigs should be protected against rejection by human T cells. Furthermore, their immune-compromised phenotype makes CAG-LEA29Y transgenic pigs an interesting large animal model for testing human cell therapies and will provide an important tool for further clarifying the LEA29Y mode of action.
Bähr, Andrea; Käser, Tobias; Kemter, Elisabeth; Gerner, Wilhelm; Kurome, Mayuko; Baars, Wiebke; Herbach, Nadja; Witter, Kirsti; Wünsch, Annegret; Talker, Stephanie C.; Kessler, Barbara; Nagashima, Hiroshi; Saalmüller, Armin; Schwinzer, Reinhard; Wolf, Eckhard; Klymiuk, Nikolai
We have successfully established and characterized a genetically modified pig line with ubiquitous expression of LEA29Y, a human CTLA4-Ig derivate. LEA29Y binds human B7.1/CD80 and B7.2/CD86 with high affinity and is thus a potent inhibitor of T cell co-stimulation via this pathway. We have characterized the expression pattern and the biological function of the transgene as well as its impact on the porcine immune system and have evaluated the potential of these transgenic pigs to propagate via assisted breeding methods. The analysis of LEA29Y expression in serum and multiple organs of CAG-LEA transgenic pigs revealed that these animals produce a biologically active transgenic product at a considerable level. They present with an immune system affected by transgene expression, but can be maintained until sexual maturity and propagated by assisted reproduction techniques. Based on previous experience with pancreatic islets expressing LEA29Y, tissues from CAG-LEA29Y transgenic pigs should be protected against rejection by human T cells. Furthermore, their immune-compromised phenotype makes CAG-LEA29Y transgenic pigs an interesting large animal model for testing human cell therapies and will provide an important tool for further clarifying the LEA29Y mode of action. PMID:27175998
Martin, Judith A; Murphy, Richard A; Power, Ronan F G
In an effort to produce phytases cost-effectively, and to determine the efficiency of a novel expression system, the genes for Aspergillus awamori ( phyA) phytase and Aspergillus fumigatus ( phyA) phytase (a putative thermostable enzyme) were cloned and overexpressed in A. awamori. Regulation of phytase expression was achieved by separately placing the genes under the transcriptional control of the glucoamylase A ( glaA) promoter of A. awamori. A gene fusion strategy was employed that involved the insertion of a hexapeptide Kex-2 protease cleavage site between the native glucoamylase and heterologous proteins and allowed for the efficient secretion and processing of the resultant chimeric proteins produced in this system by an endogenous Kex-2 protease. The genes for both of the above-mentioned phytases have already been cloned; however, this is the first report of either of the two phytases being fused with the glucoamylase gene, placed under the transcriptional control of the glaA promoter and overexpressed in A. awamori. Following transformation of A. awamori with separate expression vectors (one for each phytase), induction of phytase expression in submerged culture was effected by utilisation of a starch-containing medium. Optimisation of heterologous protein production in small shake-flask cultures involved changes in medium constituents. Maximum phytase expression levels of 200 phytase units (PU) ml(-1) and 62 PU ml(-1) for recombinantly expressed phytases from A. awamori and A. fumigatus, respectively, were obtained in crude fermentation extracts. Subsequent process scale-up to 4 l batch fermentation yielded phytase production levels comparable to those obtained on small scale. The enzyme yields herein reported demonstrate that the expression system developed and the host strain utilised were capable of expressing phytase at levels comparable to, or exceeding, previously reported data.
Berlanga-Reyes, Claudia M; Carvajal-Millán, Elizabeth; Lizardi-Mendoza, Jaime; Rascón-Chu, Agustin; Marquez-Escalante, Jorge A; Martínez-López, Ana Luisa
The laccase induced gelation of maize bran arabinoxylans at 2.5% (w/v) in the presence of insulin or beta-lactoglobulin at 0.1% (w/v) was investigated. Insulin and beta-lacto-globulin did not modify either the gel elasticity (9 Pa) or the cross-links content (0.03 and 0.015 microg di- and triferulic acids/mg arabinoxylan, respectively). The protein release capability of the gel was also investigated. The rate of protein release from gels was dependent on the protein molecular weight. The apparent diffusion coefficient was 0.99 x 10(-7) and 0.79 x 10(-7) cm(2)/s for insulin (5 kDa) and beta-lactoglobulin (18 kDa), respectively. The results suggest that maize bran arabinoxylan gels can be potential candidates for the controlled release of proteins.
Guo, Jingfei; He, Kanglai; Bai, Shuxiong; Zhang, Tiantao; Liu, Yunjun; Wang, Fuxin; Wang, Zhenying
Non-lepidopteran pests are exposed to, and may be influenced by, Bt toxins when feeding on Bt maize that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt). In order to assess the potential effects of transgenic cry1Ie maize on non-lepidopteran pest species and ecological communities, a 2-year field study was conducted to compare the non-lepidopteran pest abundance, diversity and community composition between transgenic cry1Ie maize (Event IE09S034, Bt maize) and its near isoline (Zong 31, non-Bt maize) by whole plant inspections. Results showed that Bt maize had no effects on non-lepidopteran pest abundance and diversity (Shannon-Wiener diversity index, Simpson's diversity index, species richness, and Pielou's index). There was a significant effect of year and sampling time on those indices analyzed. Redundancy analysis indicated maize type, sampling time and year totally explained 20.43 % of the variance in the non-lepidopteran pest community composition, but no association was presented between maize type (Bt maize and non-Bt maize) and the variance. Nonmetric multidimensional scaling analysis showed that sampling time and year, rather than maize type had close relationship with the non-lepidopteran pest community composition. These results corroborated the hypothesis that, at least in the short-term, the transgenic cry1Ie maize had negligible effects on the non-lepidopteran pest abundance, diversity and community composition.
Meneses, A; Manuel-Apolinar, L; Castillo, C; Castillo, E
Traditionally, the search for memory circuits has been centered on examinations of amnesic and AD patients, cerebral lesions and, neuroimaging. A complementary alternative might be the use of autoradiography with radioligands. Indeed, ex vivo autoradiographic studies offer the advantage to detect functionally active receptors altered by pharmacological tools and memory formation. Hence, herein the 5-HT(6) receptor antagonist SB-399885 and the amnesic drugs scopolamine or dizocilpine were used to manipulate memory consolidation and 5-HT(6) receptors expression was determined by using [(3)H]-SB-258585. Thus, memory consolidation was impaired in scopolamine and dizocilpine treated groups relative to control vehicle but improved it in SB-399885-treated animals. SB-399885 improved memory consolidation seems to be associated with decreased 5-HT(6) receptors expression in 15 out 17 brain areas. Scopolamine or dizocilpine decreased 5-HT(6) receptors expression in nine different brain areas and increased it in CA3 hippocampus or other eight areas, respectively. In brain areas thought to be in charge of procedural memory such basal ganglia (i.e., nucleus accumbens, caudate putamen, and fundus striate) data showed that relative to control animals amnesic groups showed diminished (scopolamine) or augmented (dizocilpine) 5-HT(6) receptor expression. SB-399885 showing improved memory displayed an intermediate expression in these same brain regions. A similar intermediate expression occurs with regard to amygdala, septum, and some cortical areas in charge of explicit memory storage. However, relative to control group amnesic and SB-399885 rats in the hippocampus, region where explicit memory is formed, showed a complex 5-HT(6) receptors expression. In conclusion, these results indicate neural circuits underlying the effects of 5-HT(6) receptor antagonists in autoshaping task and offer some general clues about cognitive processes in general.
Peichoto, María Elisa; Santoro, Marcelo Larami
Patagonfibrase is a hemorrhagic metalloproteinase isolated from the venom of the South American rear-fanged snake Philodryas patagoniensis, and is an important contributor to local lesions inflicted by this species. The tissue factor (TF)-factor VIIa complex, besides triggering the coagulation cascade, has been demonstrated to be involved in inflammatory events. Our aim was to determine whether patagonfibrase affects the expression of TF and protein disulfide isomerase (PDI), an enzyme that controls TF biological activity, at the site of patagonfibrase injection, and thus if they may play a role in hemostatic and inflammatory events induced by snake venoms. Patagonfibrase (60 μg/kg) was administered s.c. to rats, and after 3 h blood was collected to evaluate hemostasis parameters, and skin fragments close to the site of injection were taken to assess TF and PDI expression. Patagonfibrase did not alter blood cell counts, plasma fibrinogen levels, or levels of TF activity in plasma. However, by semiquantitative Western blotting, patagonfibrase increased TF expression by 2-fold, and decreased PDI expression by 3-fold in skin samples. In agreement, by immunohistochemical analyses, prominent TF expression was observed in the subcutaneous tissue. Thus, patagonfibrase affects the local expression of TF and PDI without inducing any systemic hemostatic disturbance, although that they may be involved in the local inflammatory events induced by hemorrhagic metalloproteinases. Once antivenom therapy is not totally effective to treat the local injury induced by snake venoms, modulation of the activity and expression of TF and/or PDI might become a strategy for treating snake envenomation.
Kajikawa, Akinobu; Zhang, Lin; LaVoy, Alora; Bumgardner, Sara; Klaenhammer, Todd R.; Dean, Gregg A.
Surface layer proteins of probiotic lactobacilli are theoretically efficient epitope-displaying scaffolds for oral vaccine delivery due to their high expression levels and surface localization. In this study, we constructed genetically modified Lactobacillus acidophilus strains expressing the membrane proximal external region (MPER) from human immunodeficiency virus type 1 (HIV-1) within the context of the major S-layer protein, SlpA. Intragastric immunization of mice with the recombinants induced MPER-specific and S-layer protein-specific antibodies in serum and mucosal secretions. Moreover, analysis of systemic SlpA-specific cytokines revealed that the responses appeared to be Th1 and Th17 dominant. These findings demonstrated the potential use of the Lactobacillus S-layer protein for development of oral vaccines targeting specific peptides. PMID:26509697
Matsui, Masayuki; Threlfall, Richard N; Caruthers, Marvin H; Corey, David R
ABSTRACT Optimizing oligonucleotides as therapeutics will require exploring how chemistry can be used to enhance their effects inside cells. To achieve this goal it will be necessary to fully explore chemical space around the native DNA/RNA framework to define the potential of diverse chemical modifications. In this report we examine the potential of thiophosphonoacetate (thioPACE)-modified 2′-O-methyl oligoribonucleotides as inhibitors of human huntingtin (HTT) expression. Inhibition occurred, but was less than with analogous locked nucleic acid (LNA)-substituted oligomers lacking the thioPACE modification. These data suggest that thioPACE oligonucleotides have the potential to control gene expression inside cells. However, advantages relative to other modifications were not demonstrated. Additional modifications are likely to be necessary to fully explore any potential advantages of thioPACE substitutions. PMID:26865404
Zhu, Chaobin; Trabado, Séverine; Fan, Ye; Trojan, Jerzy; Lone, Yu-Chun; Giron-Michel, Julien; Duc, Huynh-Thien
Modified melanoma B16 cells inhibited in their IGF-1 expression (B16MOD), on the contrary to the IGF-1 fully expressed parental wild-type (B16WT) counterpart, were shown to stimulate humoral as well as cellular immune responses. Among humoral components, the neutralizing and complement-fixing antibodies of IgM and essentially IgG2 (a+b) isotypes exhibited in vitro and in vivo effects upon tumour growth, while the IgG1 antibody isotype promoted enhanced tumour proliferation. As for the cellular immunity, it was found that the T CD8(+) lymphocyte subpopulation remained the main potent and long lasting immune active effector regulating tumour growth.
Birchler, J A; Bhadra, U; Rabinow, L; Linsk, R; Nguyen-Huynh, A T
A locus is described in Drosophila melanogaster that modifies the expression of the white eye color gene. This trans-acting modifier reduces the expression of the white gene in the eye, but elevates the expression in other adult tissues. Because of the eye phenotype in which the expression of white is lessened but not eliminated, the newly described locus is called the Weakener of white (Wow). Northern analysis reveals that Wow can exert an inverse or direct modifying effect depending upon the developmental stage. Two related genes, brown and scarlet, that are coordinately expressed with white, are also affected by Wow. In addition, Wow modulates the steady state RNA level of the retrotransposon, copia. When tested with a white promoter-Alcohol dehydrogenase reporter. Wow confers the modifying effect to the reporter, suggesting a requirement of the white regulatory sequences for mediating the response. In addition to being a dosage sensitive regulator of white, brown, scarlet and copia, Wow acts as a suppressor of position effect variegation. There are many dosage sensitive suppressors of position effect variegation and many dosage-sensitive modifiers of gene expression. The Wow mutations provide evidence for an overlap between the two types of modifiers.
Markelz, Nicole H.; Costich, Denise E.; Brutnell, Thomas P.
As an emerging maize (Zea mays) seedling senses light, there is a decrease in the rate of mesocotyl elongation, an induction of root growth, and an expansion of leaves. In leaf tissues, mesophyll and bundle sheath cell fate is determined, and the proplastids of each differentiate into the dimorphic chloroplasts typical of each cell type. Although it has been inferred from recent studies in several model plant species that multiple photoreceptor systems mediate this process, surprisingly little is known of light signal transduction in maize. Here, we examine two photomorphogenic responses in maize: inhibition of mesocotyl elongation and C4 photosynthetic differentiation. Through an extensive survey of white, red, far-red, and blue light responses among a diverse collection of germplasm, including a phytochrome-deficient mutant elm1, we show that light response is a highly variable trait in maize. Although all inbreds examined appear to have a functional phytochrome signal transduction pathway, several lines showed reduced sensitivity to blue light. A significant correlation was observed between light response and subpopulation, suggesting that light responsiveness may be a target of artificial selection. An examination of C4 gene expression patterns under various light regimes in the standard W22 inbred and elm1 indicate that cell-specific patterns of C4 gene expression are maintained in fully differentiated tissues independent of light quality. To our knowledge, these findings represent the first comprehensive survey of light response in maize and are discussed in relation to maize breeding strategies. PMID:14645729
Iwakiri, Ryo; Yoshihira, Kunichika; Ngadiman; Futagami, Taiki; Goto, Masatoshi; Furukawa, Kensuke
We engineered biphenyl-degrading Alcaligenes sp. strain KF711 for total degradation of pentachloroethane (PCA), which expresses a modified camphor monooxygenase and a hybrid dioxygenase consisting of TodC1 (a large subunit of toluene dioxygenase of Pseudomonas putida F1) and BphA2-BphA3-pbhA4 (a small subunit, ferredoxin and ferredoxin reductase of biphenyl dioxygenase, respectively, in strain KF707). Modified camphor monooxygenase genes (camCAB) were supplied as a plasmid and the todC1 gene was integrated within the chromosomal bph gene cluster by a single crossover recombination. The resultant strain KF711S-3cam dechlorinated PCA to trichloroethene by the action of the modified camphor monooxygenase under anaerobic conditions. The same strain subsequently degraded trichloroethene formed oxidatively by the action of the Tol-Bph hybrid dioxygenase under aerobic conditions. Thus sequential anaerobic and aerobic treatments of the KF711S-3cam resting cells resulted in efficient and total degradation of PCA.
Garzino, V; Pereira, A; Laurenti, P; Graba, Y; Levis, R W; Le Parco, Y; Pradel, J
Variegation in Drosophila is a manifest illustration of the important role played by chromatin structure in gene expression. We have isolated mutants of modulo (mod) and shown that this gene is a dominant suppressor of variegation. Null mutants are recessive lethal with a melanotic tumour phenotype. The mod protein directly binds DNA, which indicates that it may serve to anchor multimeric complexes promoting chromatin compaction and silencing. Using a specific monoclonal antibody we examined by immunocytochemistry the accumulation pattern of mod protein during embryogenesis. The protein is first detected before the blastoderm cellularization in all somatic nuclei, precisely when pericentromeric heterochromatin becomes visible. After the first cell division, mod protein is expressed in lineages of specific embryonic primordia. Based on its dominant phenotype, expression pattern and DNA-binding activity of its product, we propose that mod regulates chromatin structure and activity in specific cell lineages. Images PMID:1425581
Isbel, Luke; Whitelaw, Emma
Endogenous retrovirsuses (ERVs) have long been known to influence gene expression in plants in important ways, but what of their roles in mammals? Our relatively sparse knowledge in that area was recently increased with the finding that ERVs can influence the expression of mammalian resident genes by disrupting transcriptional termination. For many mammalian biologists, retrotransposition is considered unimportant except when it disrupts the reading frame of a gene, but this view continues to be challenged. It has been known for some time that integration into an intron can create novel transcripts and integration upstream of a gene can alter the expression of the transcript, in many cases producing phenotypic consequences and disease. The new findings on transcriptional termination extend the opportunities for retrotransposons to play a role in human disease.
Marzábal, Pau; Gas, Elisabet; Fontanet, Pilar; Vicente-Carbajosa, Jesús; Torrent, Margarita; Ludevid, M Dolores
Maize PBF (prolamin-box binding factor) belongs to the Dof class of plant specific transcription factors containing one highly conserved zinc finger DNA-binding domain, called Dof (DNA binding with one finger) domain. Maize PBF trans-activates the gamma-zein gene (gammaZ) promoter in developing maize seeds as shown by transient expression in maize endosperms. Co-transfection of a gammaZ:GUS construct with 35S:PBF resulted in a sevenfold increase in GUS expression, however, PBF mutation in Cys residues within the Dof domain abolishes both, binding to DNA and the capacity to activate gammaZ promoter. We present two pieces of evidence that PBF transactivates gammaZ promoter by binding to the Pb3 motif (TGTAAAG). First, recombinant Dof domain of PBF (bdPBF) specifically recognized Pb3 site as shown by gel mobility shift assays and second, co-expression of PBF with gammaZ promoter mutated in Pb3 motif suppressed PBF trans-activation capacity. Immunocytochemical analysis on developing endosperm sections shows that PBF is localized in the nuclei of the peripheral layer cells of starchy endosperm, the tissue in which the initial accumulation of gamma-zein protein occurs. By contrast, PBF is detected in the cytosol of the starchy endosperm cells newly differentiated from aleurone daughter cells, where gamma-zein was absent. Taken together these data indicate that maize PBF plays an essential role in the regulation of the temporal and spatial expression of gammaZ gene.
Miller, Craig S; Houff, Sidney A; Hopper, Jason; Danaher, Robert J; Gurwell, Julie A; Lin, Yushun; Vega, Nubia; Berger, Joseph R
Natalizumab-associated progressive multifocal leukoencephalopathy in multiple sclerosis (MS) occurred in two individuals also treated with interferon β1a, raising concerns about the interaction of these disease-modifying agents and leading to the recommendation to avoid their concomitant administration. However, type I interferons are antiviral. Using a real-time quantitative polymerase chain reaction for the detection and quantification of the John Cunningham virus (JCV), DNA in peripheral blood mononuclear cells (PBMCs), and urine in MS patients, we tested the hypothesis that MS disease-modifying drugs (DMD) qualitatively and quantitatively alter JCV prevalence and viral copy numbers. Two hundred thirty-nine patients were enrolled in a cross-sectional study in which blood and urine specimens were collected at a single time and 37 newly diagnosed, treatment-naïve MS patients were enrolled in a longitudinal study in which specimens were obtained at diagnosis and 6 months after treatment initiation. JCV DNA was detected in PBMCs of only two patients (0.07 %), but was commonly detected in the urine (46.8 %) in this population. There was no effect of DMDs on blood or urinary JCV prevalence or viral copy numbers with either glatiramer acetate (Copaxone®) or interferon-β therapy (Avonex®, Betaseron®, or Rebif®). The small number of patients on other therapies precluded meaningful comment about their effects. No obvious effect of the platform DMDs on JCV prevalence was observed even for the interferon-βs.
Le Tallec, Thomas; Perret, Martine; Théry, Marc
Among anthropogenic pressures, light pollution altering light/dark cycles and changing the nocturnal component of the environment constitutes a threat for biodiversity. Light pollution is widely spread across the world and continuously growing. However, despite the efforts realized to describe and understand the effects of artificial lighting on fauna, few studies have documented its consequences on biological rhythms, behavioral and physiological functions in nocturnal mammals. To determine the impacts of